Expression of the major fas family and Bcl-2 family of proteins in epithelial ovarian cancer (EOC) and their correlation to chemotherapeutic response and outcome.

ABSTRACT

Platinum-based chemotherapeutic drugs trigger apoptosis, and deregulation of apoptotic pathways may contribute to chemoresistance. We investigated the role of major Fas and Bcl-2 family members as predictors of response to platinum-based chemotherapy in epithelial ovarian cancer (EOC). The expression of Fas, FasL, FAP-1, Bax, Bcl-2, and Bcl-X(L) was analyzed in 35 women with EOC at the transcript level by semiquantitative RT-PCR and at the protein level by immunohistochemistry. The apoptotic index was determined by TUNEL assay. The response to chemotherapy was documented and at the end of six cycles of chemotherapy. Based on their response, two groups were identified primary chemosensitive (n = 20) and primary chemoresistant (n = 15). Further, after a follow-up of 12-46 months, two groups were identified no evidence of disease (n = 10) and evidence of disease (n = 25). The primary chemoresistant tumors in comparison to the chemosensitive tumors had significantly lower levels of Fas transcript (p = 0.026), Bax transcript (p = 0.042) and Bcl-2 protein (p = 0.038) and higher levels of Bcl-X(L) (p = 0.040). The apoptotic index revealed a significant inverse correlation only with Bcl-X(L) protein levels (p = 0.003). Patients with evidence of disease at last follow-up in comparison to those with no evidence of disease showed lower Bax transcript (p = 0.012), Bcl-2 protein (p = 0.014) and lower apoptotic index (p = 0.005) and higher Bcl-X(L) protein levels (p = 0.023). In conclusion, Bcl-2 family members and apoptotic index are useful in prediction of response to chemotherapy in EOC. These initial observations need to be validated in large-scale studies.