Expression of the retinoblastoma-related gene Rb2/p130 in the pathogenesis of serous carcinoma of the ovary

Objective: The purpose of this study was to evaluate the immunohistochemical Rb2/p130 expression in a series of benign, borderline, and malignant ovarian tumors. Study Design: Seventy-six operative specimens were analyzed. Frequencies and percents were calculated for variables by each of the 5 disease stage groups in increasing severity and again for the disease stage groups collapsed into benign (serous cystadenoma or endosalpingosis), low-grade [serous borderline tumors (SBT) or low-grade serous carcinoma (LGSC)] and high-grade serous carcinoma. Results: There was no loss of expression in benign serous cystadenomas (0/18). Ten percent of SBT's (2/20), 47% of LGSC's (9/19), and 16% of HGSC's (3/16) had loss of expression. There was a significant difference in the expression during the progression from cystadenoma to SBT to LGSC. Conclusions: Loss of Rb2/p130 expression is a rare event in benign cystadenoma. The progression to LGSC is associated with a decrease in gene expression.