CA-125 – Cancer Antigen (Tumor and Blood) – Definition

Definition of Tumor Maker CA-125 Cancer antigen 125, a protein often elevated in the blood circulation when certain cancers are growing in the body. The cells of the ovaries, uterus, and fallopian tubes produce CA-125; consequently Cancer antigen 125 levels rise in ovarian cancer, endometrial cancer (cancer of the uterus), and cervical cancer. The most pronounced elevation occurs with ovarian cancer. However, numerous factors other than cancer […]

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Carcinoembryonic Antigen (CEA) – Tumor Marker

Definition of Carcinoembryonic Antigen A protein present in the blood circulation with certain types of cancer. In this regard, Carcinoembryonic antigen (CEA) serves as a tumor marker. The cancers associated with elevated blood CEA levels are carcinomas of the colon and rectum (colorectal cancer), pancreas, stomach, breast, and lung. The developing fetus also produces CEA, as […]

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Antigen – Definition, Cancer and Antibody

Definition of Antigens A molecule that resides on the surface of a cell membrane and is capable of stimulating an immune response. Antigen molecules are either lipoproteins (lipid and protein) or glycolipids (lipid and glucose). Each cell has numerous antigens that that identify it to the immune system. Cells that belong to the body bear antigens that mark […]

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Human Leukocyte Antigens (HLAs)

Human Leukocyte Antigens Definition Human Leukocyte Antigens are unique proteins (antigens) present on every nucleated cell (cell that has a nucleus) in the body. Also called histocompatibility locus antigens, HLAs allow the immune system to identify cells as self (belonging to the body). Genes on chromosome 6, in a region called the major histocompatibility complex (mhc), regulate HLAs. […]

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Blood Type – A, B, 0, AB, ABO – Percentages Among Americans

Definition of Blood Type Blood Type – the pattern of specialized proteins, called agglutinogens or antigens, present on the surface of the red blood cells (erythrocytes). The presence of antigens on the erythrocytes causes the immune system to create oppositional antibodies, which will attack cells bearing the opposing antigens. Antigens and corresponding antibodies begin to develop shortly following birth. […]

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Lymphocytes – Definition, T-cells, B-cells

Definition of Lymphocytes A type of leukocyte (white blood cell) that primarily resides in the lymph and lymph tissues. Lymphocytes are the body’s primary immune defense and move through the lymph in response to antigens and pathogens. When more rapid deployment is necessary, lymphocytes enter the bloodstream. About 1 percent of the body’s lymphocyte population […]

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Prostate – Specific Antigen (PSA)

Definition of Prostate-specific Antigen (PSA) An enzyme prostate gland cells produce. Prostatic fluid, the cumulative secretions of prostate gland cells, contains high levels of PSA. PSA acts on the jellylike substance that encases sperm during their storage in the seminal vesicles, liquefying the substance when the sperm mix with prostatic fluid in the urethra during ejaculation. This action […]

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