Tumor antigens with unusual glycosylation - tumor cells may have shorter or less branched sugar chains of lack terminal sialic acid. Mucins are heavily glycosylated molecules found on some tumors, especially breast cancers. I is associated with poor prognosis. From the Immune System Areas such as the brain are protected from an immune response by the blood-brain barrier and make good sites for tumor cell growth. Also, some tumors make thick capsules that impede immune responses.
Some tumors secrete tumor growth factor-beta which is immunosuppressive.
In the 1800s, found that tumors sometimes regressed in cancer patients who had bacterial infections. Tried to vaccinate cancer patients with killed bacteria to induce a protective immune response. BCG vaccine for TB inhibits bladder cancer. Anti-proliferative effect Activation of CD8 T killer cells, macrophages, and NK cells 2. Inject the LAK cells back into the patient together with IL2.