T lymphocytes and cancer cells, computer artwork. Three T lymphocyte cells (white) attached to a cancer cell. T lymphocytes are a type of white blood cell which matures in the thymus. Certain kinds of T lymphocytes can recognise specific sites (antigens) on the surface of cancer cells or pathogens and bind to them. They can then destroy the cancer cells, or signal for other immune system cells to eliminate them. The genetic changes that cause a cell to become cancerous lead to the presentation of tumour antigens on the cell's surface.