Autoantibodies against tumor suppressor proteins

Changes in tumor suppressor genes that control cell proliferation and differentiation have consistently been discovered. Some alterations of these genes in human cancers have been found. The altered gene products may be recognized by immune response, and resulted in the presence of circulating autoantibodies. The p53 is the most intensely studied tumor suppressor gene; on the contrary, only limited evidence regarding autoantibodies against other tumor suppressor proteins can be found. This chapter will focus on the discussion of the three literature that documented the basic aspects and possible applications of autoantibodies against tumor suppressor proteins other than p53, namely retinoblastoma (RB), p16 and p73. Most of the autoantibodies against these three tumor suppressor proteins were detected in lung cancer patients. Only anti-p73 autoantibodies were detected in the sera of patients with malignancy other than lung cancer (for example,. head and neck cancer, breast cancer and bladder cancer). The positivity of these autoantibodies is low (approximately 14%), compared to that of anti-p53 autoantibodies. No significant correlation between the presence of these autoantibodies and patients' clinical manifestation were found. Nevertheless, the frequency of these autoantibodies in other malignant patients, and clinical significance and disease association of these autoantibodies need to be further investigated because of the limited evidence. Further studies on the effect of these autoanitibodies to cancer cell proliferation, their relationship to the corresponding tumor suppressor proteins and the correlation to the survival of cancer patients are necessary as well.