Cancer Testis Antigens: Novel Biomarkers and Targetable Proteins for Ovarian Cancer

Ovarian cancer is the fifth leading cause of cancer death in women and the leading cause from gynecological malignancies. Despite the recently improved outcomes of new chemotherapeutical agents in the therapy of ovarian cancer and the increased 5-year survival rate, the mortality of this malignancy disease remains unchanged. Ovarian cancer therapy is often correlated to the stage of the tumor, but the first step is usually surgical treatment. Afterward, various courses of chemotherapy and radiation are suggested. Obviously, the higher the developmental stage of the tumor, the less the probability is in eradicating it surgically, especially in relation to metastasis. It is clear that an early diagnosis of ovarian cancer is important for the survival of these patients. In order to identify ovarian cancer patients in the early stages, a number of studies are focusing on a particular class of antigens called cancer testis antigens. These antigens display high expression in tumors of different histology, but are normally restricted to the testis and have low or no expression in normal tissues. The testes are an immunologically-privileged site due to the presence of tight junctions between adjacent Sertoli cells that constitute the blood-testis barrier, which prevents auto-immune reactions. In the past few years, some of these antigens were demonstrated to be very promising for the early diagnosis and development of vaccines for ovarian cancer. This review aims to underline the most reliable cancer testis antigens under investigation at this moment.