noun, plural: tumor antigens
A substance, usually a polypeptide or a carbohydrate, produced in tumor cells, capable of inducing immune response in the host.
Tumor antigens are produced in the tumor cells, and found on the surface of tumor cells. They serve as a signal that the cell has to be destroyed before it proliferates or metastasize.
At present, tumor antigens are used to identify tumor cells. For instance, alphafetoprotein (a tumor antigen) is found in germ cell tumors, CA-125 in cancer cells of the ovary, MUC-1 in cancer cells of the breast, etc.
Word origin: tumor + antigen.
See also: antigen