Developmentally restricted differentiation antigens are targets for immunotherapy in epithelial ovarian carcinoma.

Developmentally restricted differentiation antigens or cancer-placental antigens, tastin and bystin, are components of an adhesion molecule that plays a critical role in the implantation of the embryo to the uterus. Cell adhesion molecules have been implicated in the metastasis of carcinomas and could be critical targets for immunotherapy in epithelial ovarian carcinomas (EOCs). Our objectives were to define the expression of tastin and bystin proteins in EOCs. Expression of tastin and bystin mRNA in a panel of human tissues and 70 EOC specimens was investigated using qualitative polymerase chain reaction. Amplification products were confirmed by sequencing. Validation of results was performed using immunohistochemical analysis of tastin and bystin applied on a tissue microarray of 202 EOC tissues. The distribution of tastin and bystin expression and clinicopathologic variables were analyzed. Survival probabilities were estimated using the Kaplan-Meier method and statistical significance was determined by performing the logrank test. Expression of tastin and bystin was restricted to placental and testis tissue by qualitative polymerase chain reaction. Of the 70 EOC specimens tested with polymerase chain reaction, 89% and 94% expressed tastin and bystin, respectively. Immunoexpressions of tastin and bystin protein were observed in 69% and 80 % of the ovarian tumors, respectively. Tastin and bystin expression in Stage I/II disease were 66% and 67% compared with 69% and 81% in Stage III/IV disease, respectively. The tissue-restricted expression of tastin and bystin and their abundant expression in EOCs and advanced-stage disease make these developmentally restricted antigens attractive targets for antigen-specific immunotherapy in EOCs.