·        

33.2 Tumor antigens

These are the antigens produced in tumor cells. Tumor antigens are classified based on how they express. Oncogenes and mutated tumor suppressor genes are identified as tumor antigens.

•  Tumor specific antigens – are the ones that do not express on normal cells but only on tumor cells.

•  Tumor associated antigens -are the ones that express on tumor as well as normal cells.

•  Antigens of oncogenic viruses - Oncogenic viruses such as Epstein – Barr virus, human papillomavirus and papovaviruses are associated with certain types of cancers in humans and animals. The end products of these oncogenic viruses act as tumor antigens and induce immunogenic response. This concept of immune response against virus induced cancers has paved way for the synthesis of vaccines against the tumor causing viruses.

•  Oncofoetal antigens - These are the proteins that are highly expressed in cancer cells as well as in foetus undergoing development but are absent in the adult cell.

•  Tissue specific differentiation antigens - These are tissue specific molecules expressed only on normal cells of origin and are not expressed on cells from other tissues.

33.3 Immune response to tumors

Tumor Immune response mostly occurs in two forms either by innate immune response or by adaptive immune response.