What is Cancer

Defining Cancer
 
Cancer is a term used for diseases in which abnormal cells divide without control and are able to invade other tissues. Cancer cells can spread to other parts of the body through the blood and lymph systems. 
 
Cancer is not just one disease but many diseases. There are more than 100 different types of cancer. Most cancers are named for the organ or type of cell in which they start - for example, cancer that begins in the colon is called colon cancer; cancer that begins in basal cells of the skin is called basal cell carcinoma.


Prevalence
 
Cancer is, in general, more common in industrialized nations, but there has been a growth in cancer rates in developing countries, particularly as these nations adopt the diet and lifestyle habits of industrialized countries. Over one million people in the United States get cancer each year. Anyone can get cancer at any age; however, about 80 percent of all cancers occur in people over the age of fifty-five.

Cancer can affect any site in the body. About one hundred human cancers are recognized. The four most common cancers in the United States are: lung, colon/rectum, breast, and prostate . Together, these cancers account for over 50 percent of total cancer cases in the United States each year.

 There is a marked variation among countries in incidence of different cancers. Most of the variation in cancer risk among populations, and among individuals, is due to environmental factors, such as cigarette smoking and certain dietary patterns, that can affect one's risk of developing cancer. For example, individuals living in Australia have the highest worldwide lifetime risk of skin cancer, at over 20 percent, due to the high level of exposure to the sun of people in Australia. People in India have twenty-five times the average risk of developing oral cancer sometime during their lives due to the popularity of chewing tobacco in that country. In fact, India has the world's highest incidence of oral cancer, with 75,000 to 80,000 new cases a year. The population of Japan has the highest rates of stomach cancer in the world due to the high consumption of raw fish by the Japanese.



Cancer types can be grouped into broader categories. The main categories of cancer include:

*Carcinoma - cancer that begins in the skin or in tissues that line or cover internal organs.


*Sarcoma - cancer that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue.


*Leukemia - cancer that starts in blood-forming tissue such as the bone marrow and causes large numbers of abnormal blood cells to be produced and enter the blood.


*Lymphoma and myeloma - cancers that begin in the cells of the immune system.


*Central nervous system cancers - cancers that begin in the tissues of the brain and spinal cord.

-Origins of Cancer:

 All cancers begin in cells, the body's basic unit of life. To understand cancer, it's helpful to know what happens when normal cells become cancer cells.

The body is made up of many types of cells. These cells grow and divide in a controlled way to produce more cells as they are needed to keep the body healthy. When cells become old or damaged, they die and are replaced with new cells.


However, sometimes this orderly process goes wrong. The genetic material (DNA) of a cell can become damaged or changed, producing mutations that affect normal cell growth and division. When this happens, cells do not die when they should and new cells form when the body does not need them. The extra cells may form a mass of tissue called a tumor.

Not all tumors are cancerous; tumors can be benign or malignant.
 
*Benign tumors aren't cancerous. They can often be removed, and, in most cases, they do not come back. Cells in benign tumors do not spread to other parts of the body.
*Malignant tumors are cancerous. Cells in these tumors can invade nearby tissues and spread to other parts of the body. The spread of cancer from one part of the body to another is called metastasis.

Some cancers do not form tumors. For example, leukemia is a cancer of the bone marrow and blood. 

Let's Know More About Cancer

Growth and Spread of Cancer :

 the division of cancer cells (left and right) and two healthy white blood cells (above and below). In normal cells, cell division is balanced by cell death, but cancerous cells continue to divide and accumulate, damaging nearby tissues.

 Cancer develops when cells in a particular part of the body begin to grow out of control. Normal body cells grow, divide, and die in an orderly way. Cancer cells, however, continue to grow and divide without dying. Instead, they outlive normal cells and continue to form new abnormal cancer cells. As most cancer cells continue to grow, they lump together and form an extra mass of tissue. This mass is called a malignant tumor.

As a malignant tumor grows, it damages nearby tissue. Some cancers, like leukemia, do not form tumors. Instead, these cancer cells involve the blood and blood-forming organs and circulate through other tissues, where they grow.
Cancer can begin in one part of the body and spread to others. The spread of a tumor to a new site is called metastasis. This process occurs as cancer cells break away from a tumor and travel through the bloodstream or the lymph system to other areas of the body. Once in a new location, cancer cells continue to grow out of control and form a new malignant tumor. 

And Now , We will see How Cancer Growth 

 *Causes of Cancer:

The exact cause of cancer is not known. Most cancers result from permanent damage to genes or from mutations, which occur either due to internal factors, such as hormones , immune conditions, metabolism , and the digestion of nutrients within cells, or by exposure to environmental or external factors. A chemical or other environmental agent that produces cancer is called a carcinogen.

   Also Cancer can be caused by factors such as:

*Aging : Old age causes a significant increase in the probability of cancer since most cancers occur above the age of 65. However, cancer can occur at any age as well.
 
*Tobacco use : Tobacco is one of the most common and preventable factors in cancer-related deaths. It accounts for more than 180,000 deaths in the US every year.


 
*Sunlight : The Sun emits many types of harmful radiation but Ultra Violet radiation is the most dangerous in terms causing Cancer. It causes degeneration of the skin which leads to skin cancer.
 
*Radiation : Apart from sun’s radiation, there are other sources of radiation on earth, including ionizing radiation, radioactive fallout, Radon gas and X rays. Ionizing radiation is caused by rays entering from outer space. Radioactive fallout occurs due to accidents at Nuclear plants or while testing atomic weapons. Radon gas is found in rocks and earth and is the primary cause of Cancer in miners. X rays are used in medical procedures so are not extremely harmful if exposed with appropriate measures.
 
*Chemical industry : There are several other chemicals found in the paint industry or construction work which can also lead to Cancer.


 
*Viruses : Certain viruses and bacteria can also be the cause of Cancer.
Hormone supplements : Certain hormone supplements prescribed by doctors, such as estrogen and progestin, can have significant side effects which may lead to Cancer.
 
*Family history : Not all but certain types of Cancer can be passed on through genes and may affect multiple generations. These include melanoma (skin cancer) and cancers of the breast, ovary, colon and prostate.
 

*Alcohol consumption : Having large amounts of Alcohol can also lead to Cancer.
 




*Health imbalance : Poor diet or being overweight can also be the cause of Cancer.



These are not the only causes of Cancer however, but they are the primary reasons and people who have them or work in Cancer causing environments would be well-advised to consult a doctor. 


Prevention :
All cancers caused by cigarette smoking and heavy use of alcohol could be prevented completely. Approximately 30 percent of all cancers worldwide are due to tobacco use. Many of the skin cancers could be prevented by protection from sunlight. Certain cancers that are related to infectious exposures, such as HBV, HPV, HIV, and Helicobacter could be prevented through behavioral changes, vaccines , or antibiotics . Research shows that about 30 to 40 percent of all cancers worldwide are due to dietary factors and lack of physical activity, including obesity, and could therefore have been prevented. By making changes in regard to diet, exercise, healthy weight maintenance, and tobacco use, the incidence of cancer around the world could be reduced by 60 to 70 percent 

Discovery Helps Explain Why Chemo Causes Drop in Platelet Numbers

  Scientists at the Walter and Eliza Hall Institute have identified a way that chemotherapy causes platelet numbers to drop, answering in the process a decade-old question about the formation of platelets, tiny cells that allow blood to clot.

Healthy bone marrow (top) contains many cell types including platelet-producing megakaryocytes (brown). The pro-survival protein Bcl-xL is important for keeping megakaryocytes alive. After chemotherapy (below) many cell types in the bone marrow, including megakaryocytes, are killed through a process requiring the pro-death proteins Bax and Bak. Platelet numbers can be depleted in the blood by chemotherapy because of its toxicity for both platelets and megakaryocytes. (Credit: Walter and Eliza Hall Institute of Medical Research)

 Platelets are formed by a process called 'shedding' where small fragments break off megakaryocytes (large cells normally found in the bone marrow).


Drs Emma Josefsson, Chloé James and Benjamin Kile from the institute's Molecular Medicine and Cancer and Haematology divisions have been investigating how the survival of platelet- forming megakaryocytes is controlled at a molecular level.

The life-or-death decisions of cells are controlled by the Bcl-2 family of proteins. Some 'pro-death' Bcl-2 family proteins cause cells to die, while an opposing 'pro-survival' faction prevents cell death, allowing cells to survive.

In the past decade it has been thought that platelets are formed by megakaryocytes through a process similar to cell death, Dr Josefsson said. "Our research tested this assumption by examining the molecules that are required for programmed cell death. We found that, at a molecular level, platelet formation does not occur by a death-like process.

"We found that pro-death Bcl-2 family proteins were not required for platelet formation from megakaryocytes," Dr Josefsson said. "In fact, pro-survival Bcl-2 family proteins are essential for keeping megakaryocytes alive so they can make platelets."

 
Institute scientist Professor Don Metcalf has researched blood formation for the past 50 years and was part of the research team. "For the past decade many researchers around the world have been wondering what role Bcl-2-family proteins play in platelet formation," he said. "This study is important for resolving a longstanding debate about platelet formation, and in the long term may lead to new strategies to prevent chemotherapy-induced thrombocytopenia (a deficiency in platelets). "

Low platelet numbers are a side-effect of chemotherapy and, whilst this has long been ascribed to the death of megakaryocytes and their precursors, the mechanisms responsible have remained unclear. The research team showed that chemotherapy kills megakaryocytes by its action on Bcl-2 family proteins, Dr Josefsson said. 
"Our work has shown that chemotherapy activates 'pro-death' Bcl-2 proteins to kill megakaryocytes, meaning patients are less capable of producing platelets as they recover from cancer treatment." The research was published in the Journal of Experimental Medicine.



The research was supported by the National Health and Medical Research Council, the Sylvia and Charles Viertel Foundation, the Leukaemia Foundation of Australia, the Leukemia & Lymphoma Society (USA), the Swedish Research Council, the European Molecular Biology Organisation, the Victorian Cancer Agency, Cancer Council Victoria, the Australian Cancer Research Fund, the Victorian Government and the Australian Government.

Shark Compound Proves Potential as Drug to Treat Human Viruses, Says Researcher

   A compound initially isolated from sharks shows potential as a unique broad-spectrum human antiviral agent, according to a study led by a Georgetown University Medical Center investigator and reported in the Proceedings of the National Academy of Sciences Early Edition online Sept. 19.

 The compound, squalamine, has been in human clinical trials for the treatment of cancer and several eye disorders, and so has a well-known safety profile, suggesting it can be quickly tested as a new class of drugs to treat infections caused by viruses ranging from dengue and yellow fever to hepatitis B, C, and D. In both lab and animal experiments, the compound effectively demonstrated antiviral activity against these human pathogens, some of which cannot now be effectively treated.

 "To realize that squalamine potentially has broad antiviral properties is immensely exciting, especially since we already know so much from ongoing studies about its behavior in people," says the study's lead investigator, Michael Zasloff, M.D., Ph.D., professor of surgery and pediatrics at Georgetown University Medical Center and scientific director of the Georgetown Transplant Institute.

 Not only does the study offer a promising clinical advance, Zasloff might have answered the longstanding mystery of how sharks, which have a very primitive immune system, can so effectively fight the viruses that plague all living creatures.

"I believe squalamine is one of a family of related compounds that protects sharks and some other 'primitive' ocean vertebrates, such as the sea lamprey, from viruses," he says. "Squalamine appears to protect against viruses that attack the liver and blood tissues, and other similar compounds that we know exist in the shark likely protect against respiratory viral infections, and so on.  


"We may be able to harness the shark's novel immune system to turn all of these antiviral compounds into agents that protect humans against a wide variety of viruses," Zasloff says. "That would be revolutionary. While many antibacterial agents exist, doctors have few antiviral drugs to help their patients, and few of those are broadly active."

Zasloff discovered squalamine in 1993 when he was a Professor of Pediatrics and Genetics at the University of Pennsylvania searching for novel antibacterial agents. "I was interested in sharks because of their seemingly primitive but effective immune system. No one could explain why the shark was so hardy," he says. 

After he began to "play" with the compound, he realized that it had other properties that offered a new direction to treat other disorders. Zasloff found squalamine inhibited the growth of rapidly growing blood vessels, such as those found in tumor growth and certain retinal diseases such as macular degeneration and diabetic retinopathy. Squalamine was subsequently tested in these conditions, and some of those clinical trials are ongoing.

Since 1995, squalamine has been synthesized in the laboratory, a process that does not involve use of any natural shark tissue. 


Over the years, Zasloff remained interested in how squalamine acted as an immune agent in sharks. He knew that the compound, a natural cholesterol-like molecule, has a net positive electrical charge. He later discovered that when it enters cells — squalamine can access only certain cells, like those in blood vessels, capillaries, and in the liver — it "kicks off" positively-charged proteins that are bound to the negatively-charged surface of the cell's inner membrane. Some of these displaced proteins are used by viruses to replicate, and Zasloff discovered that without those proteins, a virus's life cycle is disrupted, the microbe is rendered inert, and the cell that contains it is destroyed. 

What most intrigued Zasloff is that squalamine seems so well designed to fight certain viral infections. "To me, the key to squalamine is that once in the body it times its action to match the life cycle of most viruses. Most viruses take hours to complete their life cycle, the same time period that squalamine renders tissues and organs viral resistant after administration. In addition, it acts fast to stop viral replication, clearing the body of these predators within hours," he says.

"Furthermore, because squalamine acts by making the host's tissues less receptive for infection, rather than by targeting a specific viral protein, the emergence of viral resistance would not be anticipated," Zasloff adds

To help prove the potency of squalamine, Zasloff sent the compound to researchers around the country, including investigators at the University of California, Los Angeles, Utah State University, the National Polytechnic Institute of Mexico, Northwestern University, Eastern Virginia Medical School, Fox Chase Cancer Center, and the University of Texas Medical Branch at Galveston.

In tissue culture studies squalamine was shown to inhibit the infection of human blood vessel cells by the dengue virus and human liver cells infected with hepatitis B and D, which can cause liver failure and cancer.

In animal studies, his collaborators discovered that squalamine controlled infections of yellow fever, Eastern equine encephalitis virus, and murine cytomegalovirus, and in some cases cured the animals.

  "We have not yet optimized squalamine dosing in any of the animal models we have studied and as yet we do not know the maximum protective or therapeutic benefit that can be achieved in these systems," Zasloff says.

"But we are sufficiently convinced of the promise of squalamine as an antiviral agent that we intend to take this compound into humans," he says. "It is clearly a promising drug, and is unlike, in its mechanism of action and chemical structure, any other substance currently being investigated to treat viral infections."

Zasloff is the inventor on a patent application that has been filed related to the technology described in this paper. 
 

Eight Simple And short Tips for Your Health

Important Health Tips:
 
 1-Answer the phone by left ear

.
 2-Dont take medicine with cold water.

 3-Dont have huge meals after 5 pm.

 4- Drink more water in the morning, less at night.

 5- Best sleeping time is from 10 pm to 6am

 7-Dont lie down immediately after taking medicine.

 8-When cell battery is low to last bar, dont answer the phone, as the radiation is 1000 times stronger

  



                                                     

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Unconventional Hunt for New Cancer Targets Leads to a Powerful Drug Candidate for Leukemia

Scientists at Cold Spring Harbor Laboratory (CSHL) and five other institutions have used an unconventional approach to cancer drug discovery to identify a new potential treatment for acute myeloid leukemia (AML). As reported in Nature online on August 3, the scientists have pinpointed a protein called Brd4 as a novel drug target for AML, an aggressive blood cancer that is currently incurable in 70% of patients. Using a drug compound that inhibits the activity of Brd4, the scientists were able to suppress the disease in experimental models.

The drug candidate not only displays remarkable anti-leukemia activity in aggressive disease models and against cells derived from patients with diverse, genetic subtypes of AML, but is also minimally toxic to non-cancerous cells," says CSHL scientist Chris Vakoc, M.D., Ph.D., who led the team. "The drug is currently being developed for therapeutic use for cancer patients by Tensha Therapeutics and is expected to enter clinical trials within two years."


The protein target identified in the RNAi screen described in the current study, Brd4—which contains a distinct domain or region known as a bromodomain—is a member of the BET family of proteins, which help regulate gene expression. By "reading" certain epigenetic marks or chemical tags attached to chromatin—the combined package of DNA and proteins around which it is coiled within the cell's nucleus—Brd4 helps control the pattern of which genes are switched on and how they work.

"Cancer is clearly a genetic disease, but we also appreciate that epigenetic changes in how genes are expressed contribute to the uncontrolled growth of cancer cells," says Vakoc. Cancer cells exploit this altered epigenetic landscape to drive their cell-growth programs.

Vakoc and other scientists have seized on the idea of interfering with this epigenetic dependency to turn the tables on cancer. "Epigenetic alterations acquired during cancer progression are potentially reversible and therefore susceptible to drug intervention," he explains. With this insight as the backbone of their strategy to find new therapies for cancer, "we began to systematically search for what the cancer needs to keep itself going, to find a way to shut down that cancer-fueling factor and develop a new therapy."

RNAi screening exposes chink in AML's armor

To do so, the team turned to RNAi screening in mouse models of AML, an approach developed and perfected previously in the laboratories of Scott Lowe and Greg Hannon at CSHL. In the RNAi screen, small hairpin-shaped pieces of RNA (shRNA) that can shut off specific genes—in this case, those that encode epigenetic proteins—are introduced into mice that harbor leukemia-causing mutations.
In the current study, the mice carried the oncogene Nras as well as rearranged forms of the MLL gene – mutations often found in patients whose leukemias are resistant to standard chemotherapy, and hence, associated with a poor prognosis. In the experimental model employed by the team, the shRNAs were induced, or switched on, in the leukemic mice by supplementing their drinking water with the drug doxycycline.

"Inducing an shRNA that shuts down a gene required for the survival of leukemic cells can lead to complete disease remission," explains Johannes Zuber, M.D., a former CSHL postdoctoral researcher in the Lowe laboratory who helped develop this approach and who has recently established his own group at The Research Institute of Molecular Pathology (IMP) in Vienna. "This ability to use shRNA to simulate the effect of an anti-cancer drug illustrates the power of this approach."

While refining this approach, Zuber, Lowe and colleagues identified a protein called Myb as another potential therapeutic target for AML, as reported in a recently published paper. The work, which shows that suppressing the activity of Myb also eradicates AML in mice, set the stage for developing the screen in the current study that identified Brd4 as a druggable target for AML.

In a single experiment in which they screened more than 1000 shRNAs targeting 243 known epigenetic regulators of chromatin, the team of scientists focused in on one target–Brd4. Suppressing Brd4 with a shRNA led to a dramatic cell cycle arrest and death of leukemic cells, a marked delay in leukemia progression, and significantly extended the survival of leukemic animals.

Shutting down Brd4, the team confirmed, derailed a cellular process considered to be the hallmark of AML–the aberrant self-renewal of leukemic stem cells and their failure to complete their differentiation, or maturation, process. "We found that suppressing Brd4 in turn depletes the level and activity of a protein called Myc, which is thought to maintain leukemic stem cells," explains Junwei Shi, a graduate student in Vakoc's laboratory who worked with Zuber to spearhead these efforts.

A novel drug candidate for AML

These discoveries prompted a collaboration between the CSHL team and James Bradner, M.D., an oncologist and chemical biologist at the Dana-Farber Cancer Institute, who, serendipitously, had previously developed JQ1, a small molecular inhibitor of Brd4. Working together, the groups at CSHL and Harvard Medical School found that JQ1, which reproduced all the anti-leukemic effects seen in the Brd4 shRNA experiments, was an ideal drug candidate.

"Our extensive evaluation of JQ1 sensitivity in primary human leukemia samples and in established cell lines has revealed that this first-generation compound is broadly active against diverse AML subtypes," says Vakoc, who hopes that the second generation drug-like derivatives of the compound that are now being developed will have greater clinical utility in patients. "We're also excited to have found a pharmacological way to suppress Myc, which plays a role in many oncogenic pathways and is deregulated in most cancers," says Lowe.

"This study highlights the untapped potential of RNAi screening as a drug discovery platform, which Chris and other CSHL researchers are adapting to identify druggable targets for other types of cancers such as prostate and pancreatic cancers as well as melanoma," says CSHL President Bruce Stillman, Ph.D. "The success of this approach also points to the strength of the cancer research program at CSHL where our efforts in uncovering information about what drives individual cancers in patients is being rapidly translated into developing novel therapeutics that can immediately benefit patients in the clinic."

Information About Leukemia

First We Have To Know What is Leukemia?
  
 Leukemia is a type of blood or bone marrow cancer which affects the bone marrow and lymph tissue is characterized by an abnormal increase of white blood cells. All cancers begin in cells and keeps blood and other tissues. Normally, cells grow and divide to form new cells needed by the body. When cells grow old, the cells will die and new cells will be replaced.

However, sometimes this process goes wrong, New cells form when the body does not need it, and old cells do not die when they should. This discrepancy is called leukemia, in which the bone marrow produces white blood cells are abnormal are finally urged other cells.

In 2000, approximately 256,000 children and adults around the world developed some form of leukemia, and 209,000 died from it. About 90% of all leukemia are diagnosed in adults.

 To understand cancer, it helps to know how normal blood cells form.

Normal Blood Cells

Most blood cells develop from cells in the bone marrow called stem cells. Bone marrow is the soft material in the center of most bones.

 




Stem cells mature into different kinds of blood cells. Each kind has a special job: 

 


 White blood cells help fight infection. There are several types of white blood cells.

 







Red blood cells carry oxygen to tissues throughout the body. 









  
Platelets help form blood clots that control bleeding.

   


White blood cells, red blood cells, and platelets are made from stem cells as the body needs them.When cells grow old or get damaged, they die, and new cells take their place.
 
The picture below shows how stem cells can mature into different types of white blood cells. First, a stem cell matures into either a myeloid stem cell or a lymphoid stem cell:
 
A myeloid stem cell matures into a myeloid blast. The blast can form a red blood cell, platelets, or one of several types of white blood cells.


A lymphoid stem cell matures into a lymphoid blast. The blast can form one of several types of white blood cells, such as B cells or T cells.

The white blood cells that form from myeloid blasts are different from the white blood cells that form from lymphoid blasts.


                                           

 Leukemia Cells

While in a person with leukemia, the bone marrow makes abnormal white blood cells. The abnormal cells are leukemia cells.

Unlike normal blood cells, leukemia cells don't die when they should. They may crowd out normal white blood cells, red blood cells, and platelets. This makes it hard for normal blood cells to do their work.


Now,We are going to Say The Types of Leukemia:

The types of leukemia can be grouped based on how quickly the disease develops and gets worse. Leukemia is either chronic (which usually gets worse slowly) or acute (which usually gets worse quickly):
 
Chronic leukemia: Early in the disease, the leukemia cells can still do some of the work of normal white blood cells. People may not have any symptoms at first. Doctors often find chronic leukemia during a routine checkup - before there are any symptoms.






Slowly, chronic leukemia gets worse. As the number of leukemia cells in the blood increases, people get symptoms, such as swollen lymph nodes or infections. When symptoms do appear, they are usually mild at first and get worse gradually.


Acute leukemia: The leukemia cells can't do any of the work of normal white blood cells. The number of leukemia cells increases rapidly. Acute leukemia usually worsens quickly.

The types of leukemia also can be grouped based on the type of white blood cell that is affected. Leukemia can start in lymphoid cells or myeloid cells. See the picture of these cells. Leukemia that affects lymphoid cells is called lymphoid, lymphocytic, or lymphoblastic leukemia. Leukemia that affects myeloid cells is called myeloid, myelogenous, or myeloblastic leukemia.

There are four common types of leukemia: 

chronic lymphocytic leukemia (b-cell)

*Chronic lymphocytic leukemia (CLL): CLL affects lymphoid cells and usually grows slowly. It accounts for more than 15,000 new cases of leukemia each year. Most often, people diagnosed with the disease are over age 55. It almost never affects children.  

chronic myelogenous leukemia

*Chronic myeloid leukemia (CML): CML affects myeloid cells and usually grows slowly at first. It accounts for nearly 5,000 new cases of leukemia each year. It mainly affects adults.

acute lymphoblastic leukemia

 *Acute lymphocytic (lymphoblastic) leukemia (ALL): ALL affects lymphoid cells and grows quickly. It accounts for more than 5,000 new cases of leukemia each year. ALL is the most common type of leukemia in young children. It also affects adults. 

acute myeloid leukemia

*Acute myeloid leukemia (AML): AML affects myeloid cells and grows quickly. It accounts for more than 13,000 new cases of leukemia each year. It occurs in both adults and children. 





**Hairy cell leukemia is a rare type of chronic leukemia.



Who is at risk for leukemia? 

Down syndrome

 Risk factors:

Smokers

  When you're told that you have cancer, it's natural to wonder what may have caused the disease. No one knows the exact causes of leukemia. Doctors seldom know why one person gets leukemia and another doesn't. However, research shows that certain risk factors increase the chance that a person will get this disease.

The risk factors may be different for the different types of leukemia:
     
*Radiation: People exposed to very high levels of radiation are much more likely than others to get acute myeloid leukemia, chronic myeloid leukemia, or acute lymphocytic leukemia.


*Atomic bomb explosions: Very high levels of radiation have been caused by atomic bomb explosions (such as those in Japan during World War II). People, especially children, who survive atomic bomb explosions are at increased risk of leukemia.

*Radiation therapy: Another source of exposure to high levels of radiation is medical treatment for cancer and other conditions. Radiation therapy can increase the risk of leukemia.


*Diagnostic x-rays: Dental x-rays and other diagnostic x-rays (such as CT scans) expose people to much lower levels of radiation. It's not known yet whether this low level of radiation to children or adults is linked to leukemia. Researchers are studying whether having many x-rays may increase the risk of leukemia. They are also studying whether CT scans during childhood are linked with increased risk of developing leukemia.

*Smoking: Smoking cigarettes increases the risk of acute myeloid leukemia.    


*Benzene: Exposure to benzene in the workplace can cause acute myeloid leukemia. It may also cause chronic myeloid leukemia or acute lymphocytic leukemia. Benzene is used widely in the chemical industry. It's also found in cigarette smoke and gasoline.


*Chemotherapy: Cancer patients treated with certain types of cancer-fighting drugs sometimes later get acute myeloid leukemia or acute lymphocytic leukemia. For example, being treated with drugs known as alkylating agents or topoisomerase inhibitors is linked with a small chance of later developing acute leukemia.


*Down syndrome and certain other inherited diseases: Down syndrome and certain other inherited diseases increase the risk of developing acute leukemia.


*Myelodysplastic syndrome and certain other blood disorders: People with certain blood disorders are at increased risk of acute myeloid leukemia.


*Human T-cell leukemia virus type I (HTLV-I): People with HTLV-I infection are at increased risk of a rare type of leukemia known as adult T-cell leukemia. Although the HTLV-I virus may cause this rare disease, adult T-cell leukemia and other types of leukemia are not contagious.


*Family history of leukemia: It's rare for more than one person in a family to have leukemia. When it does happen, it's most likely to involve chronic lymphocytic leukemia. However, only a few people with chronic lymphocytic leukemia have a father, mother, brother, sister, or child who also has the disease.


-----> Having one or more risk factors does not mean that a person will get leukemia. Most people who have risk factors never develop the disease.

   So,What are symptoms of leukemia?

 

Like all blood cells, leukemia cells travel through the body. The symptoms of leukemia depend on the number of leukemia cells and where these cells collect in the body.

People with chronic leukemia may not have symptoms. The doctor may find the disease during a routine blood test.

People with acute leukemia usually go to their doctor because they feel sick. If the brain is affected, they may have headaches, vomiting, confusion, loss of muscle control, or seizures. Leukemia also can affect other parts of the body such as the digestive tract, kidneys, lungs, heart, or testes.

Common symptoms of chronic or acute leukemia may include:

leukemia in children

*Swollen lymph nodes that usually don't hurt (especially lymph nodes in the neck or armpit)


*Fevers or night sweats


*Frequent infections


*Feeling weak or tired
 

*Bleeding and bruising easily (bleeding gums, purplish patches in the skin, or tiny red spots under the skin)


*Swelling or discomfort in the abdomen (from a swollen spleen or liver)


*Weight loss for no known reason


*Pain in the bones or joints

---->Most often, these symptoms are not due to cancer. An infection or other health problems may also cause these symptoms. Only a doctor can tell for sure.

 Diagnosis of Leukemia:

 
Doctors sometimes find leukemia after a routine blood test. If you have symptoms that suggest leukemia, your doctor will try to find out what's causing the problems. Your doctor may ask about your personal and family medical history.

You may have one or more of the following tests:  

Physical exam: Your doctor checks for swollen lymph nodes, spleen, or liver.


Blood tests: The lab does a complete blood count to check the number of white blood cells, red blood cells, and platelets. Leukemia causes a very high level of white blood cells. It may also cause low levels of platelets and hemoglobin, which is found inside red blood cells.


 

Biopsy: Your doctor removes tissue to look for cancer cells. A biopsy is the only sure way to know whether leukemia cells are in your bone marrow. Before the sample is taken, local anesthesia is used to numb the area. This helps reduce the pain. Your doctor removes some bone marrow from your hipbone or another large bone. A pathologist uses a microscope to check the tissue for leukemia cells.

 


 **There are two ways your doctor can obtain bone marrow. Some people will have both procedures during the same visit:


Bone marrow aspiration: The doctor uses a thick, hollow needle to remove samples of bone marrow.


Bone marrow biopsy: The doctor uses a very thick, hollow needle to remove a small piece of bone and bone marrow.

 Other Tests

The tests that your doctor orders for you depend on your symptoms and type of leukemia. You may have other tests: 

 
Cytogenetics: The lab looks at the chromosomes of cells from samples of blood, bone marrow, or lymph nodes. If abnormal chromosomes are found, the test can show what type of leukemia you have. For example, people with CML have an abnormal chromosome called the Philadelphia chromosome.


Spinal tap: Your doctor may remove some of the cerebrospinal fluid (the fluid that fills the spaces in and around the brain and spinal cord). The doctor uses a long, thin needle to remove fluid from the lower spine. The procedure takes about 30 minutes and is performed with local anesthesia. You must lie flat for several hours afterward to keep from getting a headache. The lab checks the fluid for leukemia cells or other signs of problems.

Chest x-ray: An x-ray can show swollen lymph nodes or other signs of disease in your chest.   

   How is leukemia treated?

People with leukemia have many treatment options. The options are watchful waiting, chemotherapy, targeted therapy, biological therapy, radiation therapy, and stem cell transplant. If your spleen is enlarged, your doctor may suggest surgery to remove it. Sometimes a combination of these treatments is used.
The choice of treatment depends mainly on the following:

*The type of leukemia (acute or chronic)


*Your age


*Whether leukemia cells were found in your cerebrospinal fluid

It also may depend on certain features of the leukemia cells. Your doctor also considers your symptoms and general health.

People with acute leukemia need to be treated right away. The goal of treatment is to destroy signs of leukemia in the body and make symptoms go away. This is called a remission. After people go into remission, more therapy may be given to prevent a relapse. This type of therapy is called consolidation therapy or maintenance therapy. Many people with acute leukemia can be cured.

If you have chronic leukemia without symptoms, you may not need cancer treatment right away. Your doctor will watch your health closely so that treatment can start when you begin to have symptoms. Not getting cancer treatment right away is called watchful waiting


When treatment for chronic leukemia is needed, it can often control the disease and its symptoms. People may receive maintenance therapy to help keep the cancer in remission, but chronic leukemia can seldom be cured with chemotherapy. However, stem cell transplants offer some people with chronic leukemia the chance for cure . 

leukemia in children

 Your doctor can describe your treatment choices, the expected results, and the possible side effects. You and your doctor can work together to develop a treatment plan that meets your medical and personal needs.

You may want to talk with your doctor about taking part in a clinical trial, a research study of new treatment methods.

Your doctor may refer you to a specialist, or you may ask for a referral. Specialists who treat leukemia include hematologists, medical oncologists, and radiation oncologists. Pediatric oncologists and hematologists treat childhood leukemia. Your health care team may also include an oncology nurse and a registered dietitian.

Whenever possible, people should be treated at a medical center that has doctors experienced in treating leukemia. If this isn't possible, your doctor may discuss the treatment plan with a specialist at such a center. 
Before treatment starts, ask your health care team to explain possible side effects and how treatment may change your normal activities. Because cancer treatments often damage healthy cells and tissues, side effects are common. Side effects may not be the same for each person, and they may change from one treatment session to the next.

Methods of treatment :

chemotherapy for leukemia

1-Chemotherapy;
   
Many people with leukemia are treated with chemotherapy. Chemotherapy uses drugs to destroy leukemia cells.

Depending on the type of leukemia, you may receive a single drug or a combination of two or more drugs.

 






You may receive chemotherapy in several different ways:
 

By mouth:  
Some drugs are pills that you can swallow.



Into a vein (IV): The drug is given through a needle or tube inserted into a vein.


Through a catheter (a thin, flexible tube): The tube is placed in a large vein, often in the upper chest. A tube that stays in place is useful for patients who need many IV treatments. The health care professional injects drugs into the catheter, rather than directly into a vein. This method avoids the need for many injections, which can cause discomfort and injure the veins and skin.


Into the cerebrospinal fluid: If the pathologist finds leukemia cells in the fluid that fills the spaces in and around the brain and spinal cord, the doctor may order intrathecal chemotherapy. The doctor injects drugs directly into the cerebrospinal fluid. Intrathecal chemotherapy is given in two ways:






*Into the spinal fluid: The doctor injects the drugs into the spinal fluid.


*Under the scalp: Children and some adult patients receive chemotherapy through a special catheter called an Ommaya reservoir. The doctor places the catheter under the scalp. The doctor injects the drugs into the catheter. This method avoids the pain of injections into the spinal fluid.

Intrathecal chemotherapy is used because many drugs given by IV or taken by mouth can't pass through the tightly packed blood vessel walls found in the brain and spinal cord. This network of blood vessels is known as the blood-brain barrier.

-Chemotherapy is usually given in cycles. Each cycle has a treatment period followed by a rest period. 

You may have your treatment in a clinic, at the doctor's office, or at home. Some people may need to stay in the hospital for treatment.  
The side effects depend mainly on which drugs are given and how much. Chemotherapy kills fast-growing leukemia cells, but the drug can also harm normal cells that divide rapidly: 
 
*Blood cells: 

When chemotherapy lowers the levels of healthy blood cells, you're more likely to get infections, bruise or bleed easily, and feel very weak and tired. You'll get blood tests to check for low levels of blood cells. If your levels are low, your health care team may stop the chemotherapy for a while or reduce the dose of drug. There also are medicines that can help your body make new blood cells. Or, you may need a blood transfusion.

*Cells in hair roots: Chemotherapy may cause hair loss. If you lose your hair, it will grow back, but it may be somewhat different in color and texture.


 
*Cells that line the digestive tract: Chemotherapy can cause poor appetite, nausea and vomiting, diarrhea, or mouth and lip sores. Ask your health care team about medicines and other ways to help you cope with these problems.

*Sperm or egg cells: Some types of chemotherapy can cause infertility.


Children: Most children treated for leukemia appear to have normal fertility when they grow up. However, depending on the drugs and doses used and the age of the patient, some boys and girls may be infertile as adults.


Adult men: Chemotherapy may damage sperm cells. Men may stop making sperm. Because these changes to sperm may be permanent, some men have their sperm frozen and stored before treatment (sperm banking).


Adult women: Chemotherapy may damage the ovaries. Women may have irregular menstrual periods or periods may stop altogether. Women may have symptoms of menopause, such as hot flashes and vaginal dryness. Women who may want to get pregnant in the future should ask their health care team about ways to preserve their eggs before treatment starts.

2-Radiation therapy

Radiation therapy is a cancer treatment that uses high-energy x-rays or other types of radiation to kill cancer cells or keep them from growing. There are two types of radiation therapy. External radiation therapy uses a machine outside the body to send radiation toward the cancer. Internal radiation therapy uses a radioactive substance sealed in needles, seeds, wires, or catheters that are placed directly into or near the cancer. External radiation therapy may be used to treat childhood AML that has spread, or may spread, to the brain and spinal cord. When used this way, it is called central nervous system (CNS) sanctuary therapy or CNS prophylaxis.

 3-Biological Therapy 

Some people with leukemia receive drugs called biological therapy. Biological therapy for leukemia is treatment that improves the body's natural defenses against the disease.

One type of biological therapy is a substance called a monoclonal antibody. It's given by IV infusion. This substance binds to the leukemia cells. One kind of monoclonal antibody carries a toxin that kills the leukemia cells. Another kind helps the immune system destroy leukemia cells.

For some people with chronic myeloid leukemia, the biological therapy is a drug called interferon. It is injected under the skin or into a muscle. It can slow the growth of leukemia cells.

You may have your treatment in a clinic, at the doctor's office, or in the hospital. Other drugs may be given at the same time to prevent side effects.

The side effects of biological therapy differ with the types of substances used, and from person to person. Biological therapies commonly cause a rash or swelling where the drug is injected. They also may cause a headache, muscle aches, a fever, or weakness. Your health care team may check your blood for signs of anemia and other problems.


4-Stem Cell Transplant 

Some people with leukemia receive a stem cell transplant. A stem cell transplant allows you to be treated with high doses of drugs, radiation, or both. The high doses destroy both leukemia cells and normal blood cells in the bone marrow. After you receive high-dose chemotherapy, radiation therapy, or both, you receive healthy stem cells through a large vein. (It's like getting a blood transfusion.) New blood cells develop from the transplanted stem cells. The new blood cells replace the ones that were destroyed by treatment.

Stem cell transplants take place in the hospital. Stem cells may come from you or from someone who donates their stem cells to you .



4-Targeted Therapy 

People with chronic myeloid leukemia and some with acute lymphoblastic leukemia may receive drugs called targeted therapy. Imatinib (Gleevec) tablets were the first targeted therapy approved for chronic myeloid leukemia. Other targeted therapy drugs are now used too.

Targeted therapies use drugs that block the growth of leukemia cells. For example, a targeted therapy may block the action of an abnormal protein that stimulates the growth of leukemia cells.

Side effects include swelling, bloating, and sudden weight gain. Targeted therapy can also cause anemia, nausea, vomiting, diarrhea, muscle cramps, or a rash. Your health care team will monitor you for signs of problems.

 Watchful Waiting

People with chronic lymphocytic leukemia who do not have symptoms may be able to put off having cancer treatment. By delaying treatment, they can avoid the side effects of treatment until they have symptoms.

If you and your doctor agree that watchful waiting is a good idea, you'll have regular checkups (such as every 3 months). You can start treatment if symptoms occur.

Although watchful waiting avoids or delays the side effects of cancer treatment, this choice has risks. It may reduce the chance to control leukemia before it gets worse.

You may decide against watchful waiting if you don't want to live with an untreated leukemia. Some people choose to treat the cancer right away.

If you choose watchful waiting but grow concerned later, you should discuss your feelings with your doctor. A different approach is nearly always available.