The influence of combination chemotherapy on antigen expression in ovarian cancer

The best treatment results for advanced-stage ovarian cancer patients are obtained with cytoreductive surgery followed by combination chemotherapy. However, the 5-year survival rate of only 20% clearly shows a need for new treatment modalities. At present several modes of immunotherapy for cancer are being explored such as the use of monoclonal antibodies, bispecific antibodies, or specific cytotoxic effector cells, all making use of the presence of tumor-associated antigens remaining, necessary for tumor cell recognition. The antigenic phenotype of human epithelial ovarian cancer after chemotherapy treatment is an important issue in planning potential immunotherapeutic strategies for ovarian cancer. Therefore, we compared the antigen expression in tumor specimens obtained during operation for primary epithelial ovarian tumors and tissue biopsies taken during second-look operations after the administration of combination chemotherapy. A total of 60 ovarian tumors, including 44 serous, 3 mucinous, 2 endometrioid, 1 clear cell, 6 mixed, 2 undifferentiated, and 2 granulosa cell tumors, was studied. Frozen sections of the tumor specimens were stained with 15 different monoclonal antibodies by the indirect immunoperoxidase technique and graded semiquantitatively. The results showed only limited differences in antigenic expression in tumor tissue obtained before and after chemotherapy. Because antigen expression was not altered, immunotherapy making use of these antigenic determinants will not be hampered by prior chemotherapy.