1. What is biological therapy?

Biological therapy (sometimes called immunotherapy, biotherapy, or biological response modifier therapy) is a relatively new addition to the family of cancer treatments that also includes surgery, chemotherapy, and radiation therapy. Biological therapies use the body's immune system, either directly or indirectly, to fight cancer or to lessen the side effects that may be caused by some cancer treatments.

2. What is the immune system and what are its components?

The immune system is a complex network of cells and organs that work together to defend the body against attacks by “foreign” or “non-self” invaders. This network is one of the body's main defenses against infection and disease. The immune system works against diseases, including cancer, in a variety of ways. For example, the immune system may recognize the difference between healthy cells and cancer cells in the body and works to eliminate cancerous cells. However, the immune system does not always recognize cancer cells as “foreign.” Also, cancer may develop when the immune system breaks down or does not function adequately. Biological therapies are designed to repair, stimulate, or enhance the immune system's responses.

Immune system cells include the following:

• Lymphocytes are a type of white blood cell found in the blood and many other parts of the body. Types of lymphocytes include B cells, T cells, and Natural Killer cells.

  B cells (B lymphocytes) mature into plasma cells that secrete proteins called antibodies (immunoglobulins). Antibodies recognize and attach to foreign substances known as antigens, fitting together much the way a key fits a lock. Each type of B cell makes one specific antibody, which recognizes one specific antigen.

  T cells (T lymphocytes) work primarily by producing proteins called cytokines. Cytokines allow immune system cells to communicate with each other and include lymphokines, interferons, interleukins, and colony-stimulating factors. Some T cells, called cytotoxic T cells, release pore-forming proteins that directly attack infected, foreign, or cancerous cells. Other T cells, called helper T cells, regulate the immune response by releasing cytokines to signal other immune system defenders.

  Natural Killer cells (NK cells) produce powerful cytokines and pore-forming proteins that bind to and kill many foreign invaders, infected cells, and tumor cells. Unlike cytotoxic T cells, they are poised to attack quickly, upon their first encounter with their targets.

• Phagocytes are white blood cells that can swallow and digest microscopic organisms and particles in a process known as phagocytosis. There are several types of phagocytes, including monocytes, which circulate in the blood, and macrophages, which are located in tissues throughout the body.

3. What are biological response modifiers, and how can they be used to treat cancer?

Some antibodies, cytokines, and other immune system substances can be produced in the laboratory for use in cancer treatment. These substances are often called biological response modifiers (BRMs). They alter the interaction between the body's immune defenses and cancer cells to boost, direct, or restore the body's ability to fight the disease. BRMs include interferons, interleukins, colony-stimulating factors, monoclonal antibodies, vaccines, gene therapy, and nonspecific immunomodulating agents. Each of these BRMs is described in Questions 4 to 10.

Researchers continue to discover new BRMs, to learn more about how they function, and to develop ways to use them in cancer therapy. Biological therapies may be used to:

• Stop, control, or suppress processes that permit cancer growth.
• Make cancer cells more recognizable and, therefore, more susceptible to destruction by the immune system.
• Boost the killing power of immune system cells, such as T cells, NK cells, and macrophages.
• Alter the growth patterns of cancer cells to promote behavior like that of healthy cells.
• Block or reverse the process that changes a normal cell or a precancerous cell into a cancerous cell.
• Enhance the body's ability to repair or replace normal cells damaged or destroyed by other forms of cancer treatment, such as chemotherapy or radiation.
• Prevent cancer cells from spreading to other parts of the body.

Some BRMs are a standard part of treatment for certain types of cancer, while others are being studied in clinical trials (research studies). BRMs are being used alone or in combination with each other. They are also being used with other treatments, such as radiation therapy and chemotherapy.

4. What are interferons?

Interferons (IFNs) are types of cytokines that occur naturally in the body. They were the first cytokines produced in the laboratory for use as BRMs. There are three major types of interferons—interferon alpha, interferon beta, and interferon gamma; interferon alpha is the type most widely used in cancer treatment.

Researchers have found that interferons can improve the way a cancer patient's immune system acts against cancer cells. In addition, interferons may act directly on cancer cells by slowing their growth or promoting their development into cells with more normal behavior. Researchers believe that some interferons may also stimulate NK cells, T cells, and macrophages, boosting the immune system's anticancer function.

The U.S. Food and Drug Administration (FDA) has approved the use of interferon alpha for the treatment of certain types of cancer, including hairy cell leukemia, melanoma, chronic myeloid leukemia, and AIDS-related Kaposi's sarcoma. Studies have shown that interferon alpha may also be effective in treating other cancers such as kidney cancer and non-Hodgkin lymphoma. Researchers are exploring combinations of interferon alpha and other BRMs or chemotherapy in clinical trials to treat a number of cancers.

5. What are interleukins?

Like interferons, interleukins (ILs) are cytokines that occur naturally in the body and can be made in the laboratory. Many interleukins have been identified; interleukin-2 (IL–2 or aldesleukin) has been the most widely studied in cancer treatment. IL–2 stimulates the growth and activity of many immune cells, such as lymphocytes, that can destroy cancer cells. The FDA has approved IL–2 for the treatment of metastatic kidney cancer and metastatic melanoma.

Researchers continue to study the benefits of interleukins to treat a number of other cancers, including leukemia, lymphoma, and brain, colorectal, ovarian, breast, and prostate cancers.

6. What are colony-stimulating factors?

Colony-stimulating factors (CSFs) (sometimes called hematopoietic growth factors) usually do not directly affect tumor cells; rather, they encourage bone marrow stem cells to divide and develop into white blood cells, platelets, and red blood cells. Bone marrow is critical to the body's immune system because it is the source of all blood cells.

Stimulation of the immune system by CSFs may benefit patients undergoing cancer treatment. Because anticancer drugs can damage the body's ability to make white blood cells, red blood cells, and platelets, patients receiving anticancer drugs have an increased risk of developing infections, becoming anemic, and bleeding more easily. By using CSFs to stimulate blood cell production, doctors can increase the doses of anticancer drugs without increasing the risk of infection or the need for transfusion with blood products. As a result, researchers have found CSFs particularly useful when combined with high-dose chemotherapy.

Some examples of CSFs and their use in cancer therapy are as follows:

• G–CSF (filgrastim) and GM–CSF (sargramostim) can increase the number of white blood cells, thereby reducing the risk of infection in patients receiving chemotherapy. G–CSF and GM–CSF can also stimulate the production of stem cells in preparation for stem cell or bone marrow transplants.
  
  
• Erythropoietin (epoetin) can increase the number of red blood cells and reduce the need for red blood cell transfusions in patients receiving chemotherapy.
  
  
• Interleukin-11 (oprelvekin) helps the body make platelets and can reduce the need for platelet transfusions in patients receiving chemotherapy.

Researchers are studying CSFs in clinical trials to treat a large variety of cancers, including lymphoma, leukemia, multiple myeloma, melanoma, and cancers of the brain, lung, esophagus, breast, uterus, ovary, prostate, kidney, colon, and rectum.

7. What are monoclonal antibodies?

Researchers are evaluating the effectiveness of certain antibodies made in the laboratory called monoclonal antibodies (MOABs or MoABs). These antibodies are produced by a single type of cell and are specific for a particular antigen. Researchers are examining ways to create MOABs specific to the antigens found on the surface of various cancer cells.

To create MOABs , scientists first inject human cancer cells into mice. In response, the mouse immune system makes antibodies against these cancer cells. The scientists then remove the mouse plasma cells that produce antibodies, and fuse them with laboratory-grown cells to create “hybrid” cells called hybridomas. Hybridomas can indefinitely produce large quantities of these pure antibodies, or MOABs.

MOABs may be used in cancer treatment in a number of ways:

• MOABs that react with specific types of cancer may enhance a patient's immune response to the cancer.

• MOABs can be programmed to act against cell growth factors, thus interfering with the growth of cancer cells.

• MOABs may be linked to anticancer drugs, radioisotopes (radioactive substances), other BRMs, or other toxins. When the antibodies latch onto cancer cells, they deliver these poisons directly to the tumor, helping to destroy it.

MOABs carrying radioisotopes may also prove useful in diagnosing certain cancers, such as colorectal, ovarian, and prostate.

Rituxan^® (rituximab) and Herceptin^® (trastuzumab) are examples of MOABs that have been approved by the FDA. Rituxan is used for the treatment of non-Hodgkin lymphoma. Herceptin is used to treat metastatic breast cancer in patients with tumors that produce excess amounts of a protein called HER–2. (More information about Herceptin is available in the National Cancer Institute (NCI) fact sheet Herceptin^® (Trastuzumab): Questions and Answers, which can be found at http://www.cancer.gov/cancertopics/factsheet/Therapy/herceptin on the Internet.) In clinical trials, researchers are testing MOABs to treat lymphoma, leukemia, melanoma, and cancers of the brain, breast, lung, kidney, colon, rectum, ovary, prostate, and other areas.

8. What are cancer vaccines?

Cancer vaccines are another form of biological therapy currently under study. Vaccines for infectious diseases, such as measles, mumps, and tetanus, are injected into a person before the disease develops. These vaccines are effective because they expose the body's immune cells to weakened forms of antigens that are present on the surface of the infectious agent. This exposure causes the immune system to increase production of plasma cells that make antibodies specific to the infectious agent. The immune system also increases production of T cells that recognize the infectious agent. These activated immune cells remember the exposure, so that the next time the agent enters the body, the immune system is already prepared to respond and stop the infection.

Researchers are developing vaccines that may encourage the patient's immune system to recognize cancer cells. Cancer vaccines are designed to treat existing cancers (therapeutic vaccines) or to prevent the development of cancer (prophylactic vaccines). Therapeutic vaccines are injected in a person after cancer is diagnosed. These vaccines may stop the growth of existing tumors, prevent cancer from recurring, or eliminate cancer cells not killed by prior treatments. Cancer vaccines given when the tumor is small may be able to eradicate the cancer. On the other hand, prophylactic vaccines are given to healthy individuals before cancer develops. These vaccines are designed to stimulate the immune system to attack viruses that can cause cancer. By targeting these cancer-causing viruses, doctors hope to prevent the development of certain cancers.

Early cancer vaccine clinical trials involved mainly patients with melanoma. Therapeutic vaccines are also being studied in the treatment of many other types of cancer, including lymphoma, leukemia, and cancers of the brain, breast, lung, kidney, ovary, prostate, pancreas, colon, and rectum. Researchers are also studying prophylactic vaccines to prevent cancers of the cervix and liver. Moreover, scientists are investigating ways that cancer vaccines can be used in combination with other BRMs.

9. What is gene therapy?

Gene therapy is an experimental treatment that involves introducing genetic material into a person's cells to fight disease. Researchers are studying gene therapy methods that can improve a patient's immune response to cancer. For example, a gene may be inserted into an immune cell to enhance its ability to recognize and attack cancer cells. In another approach, scientists inject cancer cells with genes that cause the cancer cells to produce cytokines and stimulate the immune system. A number of clinical trials are currently studying gene therapy and its potential application to the biological treatment of cancer. (More information about gene therapy is available in the NCI fact sheet Gene Therapy for Cancer: Questions and Answers, which can be found at http://www.cancer.gov/cancertopics/factsheet/Therapy/gene on the Internet.)

10. What are nonspecific immunomodulating agents?

Nonspecific immunomodulating agents are substances that stimulate or indirectly augment the immune system. Often, these agents target key immune system cells and cause secondary responses such as increased production of cytokines and immunoglobulins. Two nonspecific immunomodulating agents used in cancer treatment are bacillus Calmette-Guerin (BCG) and levamisole .

BCG, which has been widely used as a tuberculosis vaccine, is used in the treatment of superficial bladder cancer following surgery. BCG may work by stimulating an inflammatory, and possibly an immune, response. A solution of BCG is instilled in the bladder and stays there for about 2 hours before the patient is allowed to empty the bladder by urinating. This treatment is usually performed once a week for 6 weeks.

Levamisole is sometimes used along with fluorouracil (5–FU) chemotherapy in the treatment of stage III (Dukes–C) colon cancer following surgery. Levamisole may act to restore depressed immune function.

11. Do biological therapies have any side effects?

Like other forms of cancer treatment, biological therapies can cause a number of side effects, which can vary widely from agent to agent and patient to patient. Rashes or swelling may develop at the site where the BRMs are injected. Several BRMs, including interferons and interleukins, may cause flu-like symptoms including fever, chills, nausea, vomiting, and appetite loss. Fatigue is another common side effect of some BRMs. Blood pressure may also be affected. The side effects of IL–2 can often be severe, depending on the dosage given. Patients need to be closely monitored during treatment with high doses of IL–2. Side effects of CSFs may include bone pain, fatigue, fever, and appetite loss. The side effects of MOABs vary, and serious allergic reactions may occur. Cancer vaccines can cause muscle aches and fever.

12. Where can a person get more information about clinical trials?

Information about ongoing clinical trials involving these and other biological therapies is available from the Cancer Information Service (see below) or the clinical trials page of the NCI's Web site at http://www.cancer.gov/clinicaltrials/ on the Internet.

# # #

• National Cancer Institute Fact Sheet 7.18, Gene Therapy for Cancer: Questions and Answers ¹
  (http://www.cancer.gov/cancertopics/factsheet/Therapy/gene)
• National Cancer Institute Fact Sheet 7.45, Herceptin® (Trastuzumab): Questions and Answers ²
  (http://www.cancer.gov/cancertopics/factsheet/therapy/herceptin)
• National Cancer Institute Fact Sheet 7.46, Access to Investigational Drugs: Questions and Answers ³
  (http://www.cancer.gov/cancertopics/factsheet/Therapy/investigational-drug-access)
• Biological Therapy ⁴ (http://www.cancer.gov/cancertopics/biologicaltherapy)
• Taking Part in Cancer Treatment Research Studies ⁵
  (http://www.cancer.gov/clinicaltrials/Taking-Part-in-Cancer-Treatment-Research-Studies)
• What You Need To Know About™ Cancer ⁶
  (http://www.cancer.gov/cancertopics/wyntk/overview)

For more help, contact:

NCI's Cancer Information Service
Telephone (toll-free): 1–800–4–CANCER (1–800–422–6237)
TTY (toll-free): 1–800–332–8615
LiveHelp^® online chat: https://cissecure.nci.nih.gov/livehelp/welcome.asp

Glossary Terms

A disease caused by the human immunodeficiency virus (HIV). People with AIDS are at an increased risk for developing certain cancers and for infections that usually occur only in individuals with a weak immune system. Also called acquired immunodeficiency syndrome.

A drug used to treat some types of cancer. It is a form of interleukin-2, a cytokine made by leukocytes (white blood cells), that is made in the laboratory. Aldesleukin increases the activity and growth of white blood cells called T lymphocytes and B lymphocytes. It is a type of biological response modifier. Also called Proleukin and recombinant human interleukin-2.

A condition in which the number of red blood cells is below normal.

Any substance that causes the body to make a specific immune response.

A type of immune cell that makes proteins called antibodies, which bind to microorganisms and other foreign substances, and help fight infections. A B cell is a type of white blood cell. Also called B lymphocyte.

A type of immune cell that makes proteins called antibodies, which bind to microorganisms and other foreign substances, and help fight infections. A B lymphocyte is a type of white blood cell. Also called B cell.

A weakened form of the bacterium Mycobacterium bovis (bacillus Calmette-Guérin) that does not cause disease. BCG is used in a solution to stimulate the immune system in the treatment of bladder cancer and as a vaccine to prevent tuberculosis. Also called bacillus Calmette-Guérin.

Pertaining to biology or to life and living things. In medicine, refers to a substance made from a living organism or its products. Biologicals may be used to prevent, diagnose, treat or relieve of symptoms of a disease. For example, antibodies, interleukins, and vaccines are biologicals. Biological also refers to parents and children who are related by blood.

Treatment to boost or restore the ability of the immune system to fight cancer, infections, and other diseases. Also used to lessen certain side effects that may be caused by some cancer treatments. Agents used in biological response modifier therapy include monoclonal antibodies, growth factors, and vaccines. These agents may also have a direct antitumor effect. Also called biological therapy, biotherapy, BRM therapy, and immunotherapy.

Treatment to boost or restore the ability of the immune system to fight cancer, infections, and other diseases. Also used to lessen certain side effects that may be caused by some cancer treatments. Agents used in biological therapy include monoclonal antibodies, growth factors, and vaccines. These agents may also have a direct antitumor effect. Also called biological response modifier therapy, biotherapy, BRM therapy, and immunotherapy.

Treatment to boost or restore the ability of the immune system to fight cancer, infections, and other diseases. Also used to lessen certain side effects that may be caused by some cancer treatments. Agents used in biotherapy include monoclonal antibodies, growth factors, and vaccines. These agents may also have a direct antitumor effect. Also called biological response modifier therapy, biological therapy, BRM therapy, and immunotherapy.

The organ that stores urine.

Cancer that forms in tissues of the bladder (the organ that stores urine). Most bladder cancers are transitional cell carcinomas (cancer that begins in cells that normally make up the inner lining of the bladder). Other types include squamous cell carcinoma (cancer that begins in thin, flat cells) and adenocarcinoma (cancer that begins in cells that make and release mucus and other fluids). The cells that form squamous cell carcinoma and adenocarcinoma develop in the inner lining of the bladder as a result of chronic irritation and inflammation.

A tissue with red blood cells, white blood cells, platelets, and other substances suspended in fluid called plasma. Blood takes oxygen and nutrients to the tissues, and carries away wastes.

The soft, sponge-like tissue in the center of most bones. It produces white blood cells, red blood cells, and platelets.

A procedure to replace bone marrow that has been destroyed by treatment with high doses of anticancer drugs or radiation. Transplantation may be autologous (an individual's own marrow saved before treatment), allogeneic (marrow donated by someone else), or syngeneic (marrow donated by an identical twin).

Glandular organ located on the chest. The breast is made up of connective tissue, fat, and breast tissue that contains the glands that can make milk. Also called mammary gland.

Cancer that forms in tissues of the breast, usually the ducts (tubes that carry milk to the nipple) and lobules (glands that make milk). It occurs in both men and women, although male breast cancer is rare.

A term for diseases in which abnormal cells divide without control and can invade nearby tissues. Cancer cells can also spread to other parts of the body through the blood and lymph systems. There are several main types of cancer. Carcinoma is a cancer that begins in the skin or in tissues that line or cover internal organs. Sarcoma is a cancer that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue. Leukemia is a 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 multiple myeloma are cancers that begin in the cells of the immune system. Central nervous system cancers are cancers that begin in the tissues of the brain and spinal cord. Also called malignancy.

The Cancer Information Service is the National Cancer Institute's link to the public, interpreting and explaining research findings in a clear and understandable manner, and providing personalized responses to specific questions about cancer. Access the CIS by calling 1-800-4-CANCER (1-800-422-6237), or by using the LiveHelp instant-messaging service at https://cissecure.nci.nih.gov/livehelp/welcome.asp. Also called CIS.

A vaccine designed to prevent or treat cancer.

The individual unit that makes up the tissues of the body. All living things are made up of one or more cells.

The lower, narrow end of the uterus that forms a canal between the uterus and vagina.

Treatment with drugs that kill cancer cells.

A slowly progressing disease in which too many white blood cells (not lymphocytes) are made in the bone marrow. Also called chronic granulocytic leukemia, chronic myelogenous leukemia, and CML.

A type of research study that tests how well new medical approaches work in people. These studies test new methods of screening, prevention, diagnosis, or treatment of a disease. Also called clinical study.

The longest part of the large intestine, which is a tube-like organ connected to the small intestine at one end and the anus at the other. The colon removes water and some nutrients and electrolytes from partially digested food. The remaining material, solid waste called stool, moves through the colon to the rectum and leaves the body through the anus.

Cancer that forms in the tissues of the colon (the longest part of the large intestine). Most colon cancers are adenocarcinomas (cancers that begin in cells that make and release mucus and other fluids).

A substance that stimulates the production of blood cells. Colony-stimulating factors include granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF), and promegapoietin.

Having to do with the colon or the rectum.

The fluid that flows in and around the hollow spaces of the brain and spinal cord, and between two of the meninges (the thin layers of tissue that cover and protect the brain and spinal cord). CSF is made by tissue called the choroid plexus in the ventricles (hollow spaces) in the brain. Also called cerebrospinal fluid.

A substance that is made by cells of the immune system. Some cytokines can boost the immune response and others can suppress it. Cytokines can also be made in the laboratory by recombinant DNA technology and used in the treatment of various diseases, including cancer.

A type of immune cell that can kill certain cells, including foreign cells, cancer cells, and cells infected with a virus. Cytotoxic T cells can be separated from other blood cells, grown in the laboratory, and then given to a patient to kill cancer cells. A cytotoxic T cell is a type of white blood cell and a type of lymphocyte. Also called cytotoxic T lymphocyte and killer T cell.

The process of identifying a disease, such as cancer, from its signs and symptoms.

The amount of medicine taken, or radiation given, at one time.

Any substance, other than food, that is used to prevent, diagnose, treat or relieve symptoms of a disease or abnormal condition. Also refers to a substance that alters mood or body function, or that can be habit-forming or addictive, especially a narcotic.

A substance that is naturally produced by the kidneys, and that stimulates the bone marrow to make red blood cells. When erythropoietin is made in the laboratory, it is called epoetin alfa or epoetin beta.

The muscular tube through which food passes from the throat to the stomach.

In clinical trials, refers to a drug (including a new drug, dose, combination, or route of administration) or procedure that has undergone basic laboratory testing and received approval from the U.S. Food and Drug Administration (FDA) to be tested in human subjects. A drug or procedure may be approved by the FDA for use in one disease or condition, but be considered experimental in other diseases or conditions. Also called investigational.

A condition marked by extreme tiredness and inability to function due lack of energy. Fatigue may be acute or chronic.

A colony-stimulating factor that stimulates the production of neutrophils (a type of white blood cell). It is a cytokine that is a type of hematopoietic (blood-forming) agent. Also called G-CSF and granulocyte colony-stimulating factor.

A drug used to treat symptoms of cancer of the colon, breast, stomach, and pancreas. It is also used in a cream to treat certain skin conditions. Fluorouracil stops cells from making DNA and it may kill cancer cells. It is a type of antimetabolite. Also called 5-fluorouracil and 5-FU.

The functional and physical unit of heredity passed from parent to offspring. Genes are pieces of DNA, and most genes contain the information for making a specific protein.

Treatment that alters a gene. In studies of gene therapy for cancer, researchers are trying to improve the body's natural ability to fight the disease or to make the cancer cells more sensitive to other kinds of therapy.

Inherited; having to do with information that is passed from parents to offspring through genes in sperm and egg cells.

A substance made by the body that functions to regulate cell division and cell survival. Some growth factors are also produced in the laboratory and used in biological therapy.

A rare type of leukemia in which abnormal B-lymphocytes (a type of white blood cell) are present in the bone marrow, spleen, and peripheral blood. When viewed under a microscope, these cells appear to be covered with tiny hair-like projections.

A type of immune cell that stimulates killer T cells, macrophages, and B cells to make immune responses. A helper T cell is a type of white blood cell and a type of lymphocyte. Also called CD4-positive T lymphocyte.

A group of proteins that causes blood cells to grow and mature.

A monoclonal antibody that binds to HER2 (human epidermal growth factor receptor 2), and can kill HER2-positive cancer cells. Monoclonal antibodies are made in the laboratory and can locate and bind to substances in the body, including cancer cells. Herceptin is used to treat breast cancer that is HER2-positive and has spread after treatment with other drugs. It is also used with other anticancer drugs to treat HER2-positive breast cancer after surgery. Herceptin is also being studied in the treatment of other types of cancer. Also called trastuzumab.

An intensive drug treatment to kill cancer cells, but that also destroys the bone marrow and can cause other severe side effects. High-dose chemotherapy is usually followed by bone marrow or stem cell transplantation to rebuild the bone marrow.

Production and action of cells that fight disease or infection.

The complex group of organs and cells that defends the body against infections and other diseases.

Treatment to boost or restore the ability of the immune system to fight cancer, infections, and other diseases. Also used to lessen certain side effects that may be caused by some cancer treatments. Agents used in immunotherapy include monoclonal antibodies, growth factors, and vaccines. These agents may also have a direct antitumor effect. Also called biological response modifier therapy, biological therapy, biotherapy, and BRM therapy.

Invasion and multiplication of germs in the body. Infections can occur in any part of the body and can spread throughout the body. The germs may be bacteria, viruses, yeast, or fungi. They can cause a fever and other problems, depending on where the infection occurs. When the body’s natural defense system is strong, it can often fight the germs and prevent infection. Some cancer treatments can weaken the natural defense system.

Having to do with inflammation (redness, swelling, pain, and a feeling of heat that helps protect tissues affected by injury or disease).

Use of a syringe and needle to push fluids or drugs into the body; often called a "shot."

A biological response modifier (a substance that can improve the body's natural response to infections and other diseases). Interferons interfere with the division of cancer cells and can slow tumor growth. There are several types of interferons, including interferon-alpha, -beta, and -gamma. The body normally produces these substances. They are also made in the laboratory to treat cancer and other diseases.

One of a group of related proteins made by leukocytes (white blood cells) and other cells in the body. Interleukins regulate immune responses. Interleukins made in the laboratory are used as biological response modifiers to boost the immune system in cancer therapy. An interleukin is a type of cytokine. Also called IL.

One of a group of related proteins made by leukocytes (white blood cells) and other cells in the body. Interleukin-11 is made by support cells in the bone marrow. It causes the growth of several types of blood cells. Oprelvekin (interleukin-11 made in the laboratory) is used as a biological response modifier to increase the number of platelets, especially in patients receiving chemotherapy for cancer. Interleukin-11 is a type of cytokine. Also called IL-11.

One of a group of related proteins made by leukocytes (white blood cells) and other cells in the body. Interleukin-2 is made by a type of T lymphocyte. It increases the growth and activity of other T lymphocytes and B lymphocytes, and affects the development of the immune system. Aldesleukin (interleukin-2 made in the laboratory) is being used as a biological response modifier to boost the immune system in cancer therapy. Interleukin-2 is a type of cytokine. Also called IL-2.

One of a pair of organs in the abdomen. Kidneys remove waste from the blood (as urine), produce erythropoietin (a substance that stimulates red blood cell production), and play a role in blood pressure regulation.

Cancer that forms in tissues of the kidneys. Kidney cancer includes renal cell carcinoma (cancer that forms in the lining of very small tubes in the kidney that filter the blood and remove waste products) and renal pelvis carcinoma (cancer that forms in the center of the kidney where urine collects). It also includes Wilms tumor, which is a type of kidney cancer that usually develops in children under the age of 5.

Cancer that starts in blood-forming tissue such as the bone marrow and causes large numbers of blood cells to be produced and enter the bloodstream.

An antiparasitic drug that is also being studied in cancer therapy with fluorouracil.

A large organ located in the upper abdomen. The liver cleanses the blood and aids in digestion by secreting bile.

One of a pair of organs in the chest that supplies the body with oxygen, and removes carbon dioxide from the body.

A type of immune cell that is made in the bone marrow and is found in the blood and in lymph tissue. The two main types of lymphocytes are B lymphocytes and T lymphocytes. B lymphocytes make antibodies, and T lymphocytes help kill tumor cells and help control immune responses. A lymphocyte is a type of white blood cell.

Cancer that begins in cells of the immune system. There are two basic categories of lymphomas. One kind is Hodgkin lymphoma, which is marked by the presence of a type of cell called the Reed-Sternberg cell. The other category is non-Hodgkin lymphomas, which includes a large, diverse group of cancers of immune system cells. Non-Hodgkin lymphomas can be further divided into cancers that have an indolent (slow-growing) course and those that have an aggressive (fast-growing) course. These subtypes behave and respond to treatment differently. Both Hodgkin and non-Hodgkin lymphomas can occur in children and adults, and prognosis and treatment depend on the stage and the type of cancer.

A type of white blood cell that surrounds and kills microorganisms, removes dead cells, and stimulates the action of other immune system cells.

A form of cancer that begins in melanocytes (cells that make the pigment melanin). It may begin in a mole (skin melanoma), but can also begin in other pigmented tissues, such as in the eye or in the intestines.

Having to do with metastasis, which is the spread of cancer from the primary site (place where it started) to other places in the body.

Too small to be seen without a microscope.

A type of protein made in the laboratory that can locate and bind to substances in the body, including tumor cells. There are many kinds of monoclonal antibodies. Each monoclonal antibody is made to find one substance. Monoclonal antibodies are being used to treat some types of cancer and are being studied in the treatment of other types. They can be used alone or to carry drugs, toxins, or radioactive materials directly to a tumor.

A type of cancer that begins in plasma cells (white blood cells that produce antibodies). Also called Kahler disease, myelomatosis, and plasma cell myeloma.

The National Cancer Institute, part of the National Institutes of Health of the United States Department of Health and Human Services, is the Federal Government's principal agency for cancer research. The National Cancer Institute conducts, coordinates, and funds cancer research, training, health information dissemination, and other programs with respect to the cause, diagnosis, prevention, and treatment of cancer. Access the National Cancer Institute Web site at http://www.cancer.gov. Also called NCI.

A type of immune cell that has granules (small particles) with enzymes that can kill tumor cells or cells infected with a virus. A natural killer cell is a type of white blood cell. Also called NK cell and NK-LGL.

A feeling of sickness or discomfort in the stomach that may come with an urge to vomit. Nausea is a side effect of some types of cancer therapy.

A part of the body that performs a specific function. For example, the heart is an organ.

Having to do with the ovaries, the female reproductive glands in which the ova (eggs) are formed. The ovaries are located in the pelvis, one on each side of the uterus.

One of a pair of female reproductive glands in which the ova, or eggs, are formed. The ovaries are located in the pelvis, one on each side of the uterus.

A glandular organ located in the abdomen. It makes pancreatic juices, which contain enzymes that aid in digestion, and it produces several hormones, including insulin. The pancreas is surrounded by the stomach, intestines, and other organs.

The clear, yellowish, fluid part of the blood that carries the blood cells. The proteins that form blood clots are in plasma.

A tiny piece of a cell found in the blood that breaks off from a large cell found in the bone marrow. Platelets help wounds heal and prevent bleeding by forming blood clots. Also called thrombocyte.

A term used to describe a condition that may (or is likely to) become cancer. Also called premalignant.

In medicine, something that prevents or protects.

A gland in the male reproductive system. The prostate surrounds the part of the urethra (the tube that empties the bladder) just below the bladder, and produces a fluid that forms part of the semen.

A molecule made up of amino acids that are needed for the body to function properly. Proteins are the basis of body structures such as skin and hair and of substances such as enzymes, cytokines, and antibodies.

Energy released in the form of particle or electromagnetic waves. Common sources of radiation include radon gas, cosmic rays from outer space, medical x-rays, and energy given off by a radioisotope (unstable form of a chemical element that releases radiation as it breaks down and becomes more stable).

The use of high-energy radiation from x-rays, gamma rays, neutrons, protons, and other sources to kill cancer cells and shrink tumors. Radiation may come from a machine outside the body (external-beam radiation therapy), or it may come from radioactive material placed in the body near cancer cells (internal radiation therapy). Systemic radiation therapy uses a radioactive substance, such as a radiolabeled monoclonal antibody, that travels in the blood to tissues throughout the body. Also called irradiation and radiotherapy.

Giving off radiation.

An unstable form of a chemical element that releases radiation as it breaks down and becomes more stable. Radioisotopes may occur in nature or be made in a laboratory. In medicine, they are used in imaging tests and in treatment. Also called radionuclide.

The last several inches of the large intestine closest to the anus.

To come back or to return.

A cell that carries oxygen to all parts of the body. Also called erythrocyte and RBC.

A monoclonal antibody used to treat certain types of B-cell non-Hodgkin lymphoma and symptoms of rheumatoid arthritis. Monoclonal antibodies are made in the laboratory and can bind to substances in the body, including cancer cells. Rituximab binds to the protein called CD20, which is found on B-cells, and may kill cancer cells. Also called Rituxan.

A cancer of the bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue.

A substance that helps make more white blood cells, especially granulocytes, macrophages, and cells that become platelets. It is a cytokine that is a type of hematopoietic (blood-forming) agent. Also called GM-CSF and granulocyte-macrophage colony-stimulating factor.

A problem that occurs when treatment affects healthy tissues or organs. Some common side effects of cancer treatment are fatigue, pain, nausea, vomiting, decreased blood cell counts, hair loss, and mouth sores.

The extent of a cancer in the body. Staging is usually based on the size of the tumor, whether lymph nodes contain cancer, and whether the cancer has spread from the original site to other parts of the body.

A cell from which other types of cells develop. For example, blood cells develop from blood-forming stem cells.

Affecting cells on the surface. Not invasive.

A procedure to remove or repair a part of the body or to find out whether disease is present. An operation.

An indication that a person has a condition or disease. Some examples of symptoms are headache, fever, fatigue, nausea, vomiting, and pain.

A type of immune cell that can attack foreign cells, cancer cells, and cells infected with a virus. T cells can also help control immune responses. A T cell is a type of white blood cell. Also called T lymphocyte and thymocyte.

Having to do with treating disease and helping healing take place.

Treatment.

A group or layer of cells that work together to perform a specific function.

A poison produced by certain animals, plants, or bacteria.

The infusion of components of blood or whole blood into the bloodstream. The blood may be donated from another person, or it may have been taken from the person earlier and stored until needed.

A monoclonal antibody that binds to HER2 (human epidermal growth factor receptor 2), and can kill HER2-positive cancer cells. Monoclonal antibodies are made in the laboratory and can locate and bind to substances in the body, including cancer cells. Trastuzumab is used to treat breast cancer that is HER2-positive and has spread after treatment with other drugs. It is also used with other anticancer drugs to treat HER2-positive breast cancer after surgery. Trastuzumab is also being studied in the treatment of other types of cancer. Also called Herceptin.

An abnormal mass of tissue that results when cells divide more than they should or do not die when they should. Tumors may be benign (not cancer), or malignant (cancer). Also called neoplasm.

The small, hollow, pear-shaped organ in a woman's pelvis. This is the organ in which a fetus develops. Also called womb.

A substance or group of substances meant to cause the immune system to respond to a tumor or to microorganisms, such as bacteria or viruses. A vaccine can help the body recognize and destroy cancer cells or microorganisms.

In medicine, a very simple microorganism that infects cells and may cause disease. Because viruses can multiply only inside infected cells, they are not considered to be alive.

To eject some or all of the contents of the stomach through the mouth.

A type of immune cell. Most white blood cells are made in the bone marrow and are found in the blood and lymph tissue. White blood cells help the body fight infections and other diseases. Granulocytes, monocytes, and lymphocytes are white blood cells. Also called leukocyte and WBC.