Glossary

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Immune response: The activity of the various components of the immune system against antigens. The immune response involves B cells, T cells, Natural Killer cells and antigen processing cells, and may be specific to the antigen or nonspecific.

Immune system: The body's complex system of organs and cells that fight disease by recognizing and neutralizing foreign organisms, altered and sometimes cancerous cells, and other substances.

Immunoassay: A technique of identifying a substance based on its ability to act as an antigen.

Immunoglobulin G (IgG): The class of immunoglobulin normally present in largest amount in the blood. IgG can enter tissue space. It functions mainly against bacteria and some viruses by coating them, which speeds their uptake by other cells in the immune system.

Immunoglobulin M (IgM): The class of immunoglobulin normally present in the largest amount in the blood, after IgG. IgM works in the bloodstream and is every effective at killing bacteria.

Immunology: The study of the body's immune system.

Immunological: Pertaining to the body's immune system.

Immunoglobulins: A large family of proteins that function as antibodies.

Immunotherapy: The use of natural or manufactured substances to help the body's immune system fight disease more effectively.Types of immunotherapy include interferons, interleukins, biochemotherapy, vaccine therapy, and antibody-based therapies.

Incidence: The number of new cases of a disease occurring over a period of time, generally over the course of a year. Incidence rate: Ratio of the number of new cases of a disease to a given population each year.

Incisional biopsy: A biopsy in which only a portion of a suspicious skin lesion is removed. This method is used when the lesion is too large for excisional biopsy or when excision would destroy important tissue, as on the face or hands.

Informed consent: An ongoing process in which potential candidates for research studies or clinical trials learn about the study's key facts, including the purpose of the study, potential risks and benefits, and other treatment alternatives. The purpose of informed consent is to enable candidates to make the most appropriate decisions about beginning or continuing to participate in the study or trial, or pursuing other options.

Inguinal: Pertaining to the groin.

Institutional Review Board (IRB): An independent committee of doctors, scientists, clergy, and health care consumers located at the institution where a clinical trial is to take place. The IRB reviews the trial to make sure it is ethical and protects the rights and safety of study participants. IRBs approve and monitor almost all clinical trials in the United States.

Interferon alpha: One of three major species of interferon produced by the body. (The others are known as interferon beta and gamma.) Interferon alpha is the type that has been found to be most useful in treating forms of cancer, including melanoma, leukemia, and kidney cancer.

Interferon alfa-2a: A manufactured form of one of the types of interferon alpha. Studies have shown low-dose interferon alfa-2a delays relapse in patients with Stage II melanoma and higher-risk Stage IIB disease.

Interferon alfa-2b: A manufactured form of one of the types of interferon alpha. Studies have shown high-dose interferon alfa-2b significantly prolongs disease-free and overall survival in patients with high-risk Stage IIB and Stage III melanoma. It is an FDA-approved therapy for patients with high-risk operable Stage IIB and III melanoma.

Interferon gamma: A species of interferon that is being investigated as a component of isolated limb perfusion.

Interferons: Natural proteins produced by the normal cells of most body tissues in response to viral infections and disease, including cancer. Interferons affect immune responses and boost resistance to viral infection. Interferon therapies have been shown to help the body's immune system fight disease more effectively and may inhibit the growth of blood vessels that feed cancer cells.

Interleukin-2 (IL-2): A naturally produced protein of the immune system that stimulates the growth of specific types of white blood cells. It is an FDA-approved immunotherapy for advanced inoperable melanoma and is under study for the adjuvant treatment of high-risk melanoma.

Interleukins: A family of substances produced naturally in the body in response to infections and that help the immune system produce more infection- and cancer-fighting cells.

Internal radiation therapy: The delivery of radioactive material to a location very close to the tumor from a source placed inside the body. Methods of delivery include injection, ingestion, or implantation. Also known as brachytherapy.

Intervention group: In a clinical trial, the group assigned to receive the new treatment and compared to the control group to determine whether the new treatment is more effective than the standard treatment.

Investigational group: The intervention group in a clinical trial.

Intradermal: In the skin. An intradermal injection is given into the skin.

Intradermal nevi: Flesh-colored or light brown, dome-shaped moles whose melanocytes are confined to the dermis. They are most commonly found in adults.

Intravenous (IV): Within a vein.

Isolated limb infusion: An experimental chemotherapy treatment in blood flow to the involved limb is stopped temporarily with a tourniquet while high doses of chemotherapy drugs are injected into the artery.

Isolated limb perfusion (ILP): Chemotherapy treatment in which blood vessel surgery is used to temporarily isolate the circulation of the involved limb from the rest of the body. This blood is then mixed with high doses of chemotherapy, recirculated through a heart-lung machine, and heated for a period of time to enhance the drug's potency. The treated blood is then returned to the affected limb.

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