Most cancer drugs are cytotoxic agents. These agents selectively damage cells that are rapidly dividing. Since tumor cells are normally in a state of rapid division, this explains the ability of these agents to reduce tumor growth and in some cases bring about tumor shrinkage.
T lymphocyte (CTL): immune system cell that can destroy cancer cells and cells infected with viruses, fungi or certain bacteria. CTLs, also known as killer T cells, carry the CD8 marker. CTLs kill virus-infected cells, whereas antibodies generally target free-floating viruses in the blood. CTL responses are a proposed but unproven correlate of HIV immunity. (See also CD8+ T lymphocyte.)
chemicals that are directly toxic to cells, preventing their reproduction or growth. Cytotoxic agents can, as a side effect, damage healthy, noncancerous tissues or organs that have a high proportion of actively dividing cells – for example, bone marrow or hair follicles. These side effects limit the amount and frequency of drug administration.