• Adverse event

    An unexpected medical problem that happens during treatment with a drug or other therapy. Adverse events do not have to be caused by the drug or therapy, and they may be mild, moderate, or severe. Also called adverse effect. [NCI]
  • Angiogenesis

    Blood vessel formation. Tumour angiogenesis is the growth of new blood vessels that tumours need to grow. This process is caused by the release of chemicals by the tumour and by cells near the tumour. [NCI]
  • Antibody

    A protein created by B-cells in direct response to specific antigens. An antibody attaches itself to its respective antigen, marking it for other immune cells to “see” and destroy. [Patient Resource LLC]
  • Antigen

    A protein produced by a cell, virus or bacteria. In the case of cancer antigens, the protein or part of a protein is on the surface of the cancer cell. It alerts the immune system and causes the production of antibodies or the creation of T-cells that can recognize and potentially destroy the cancer cells expressing that antigen. [Patient Resource LLC]
  • Antigen-presenting cells (APCs)

    Special cells that digest invading cells or soluble (can be dissolved in water) protein antigens and present them to the T-cells and B-cells so they know what to attack. [Patient Resource LLC]
  • Apoptosis

    A type of cell death in which a series of molecular steps in a cell lead to its death. This is one method the body uses to get rid of unneeded or abnormal cells. The process of apoptosis may be blocked in cancer cells. Also called programmed cell death. [NCI]
  • Autophagy

    A normal process in which a cell destroys proteins and other substances in its cytoplasm (the fluid inside the cell membrane but outside the nucleus), which may lead to cell death. Autophagy may prevent normal cells from developing into cancer cells, but it may also protect cancer cells by destroying anti-cancer drugs or substances taken up by them. [NCI]