The progesterone receptor is differentially expressed in epithelial ovarian cancer and its expression correlates with patient survival.
Epithelial ovarian cancer (EOC) is the most lethal gynecologic cancer (1). We sought to identify genes associated with high-grade serous ovarian cancer (HGSC), the most common type of EOC by comparing global gene expression profiles of normal ovary with that of primary tumors from women diagnosed with HGSC using published microarray data (2, 3). We found significant differential expression of the gene encoding the progesterone receptor, PGR, in high-grade serous ovarian tumors and in epithelial ovarian cancer broadly. PGR was expressed at lower levels in tumors from patients with high-grade serous ovarian cancer as compared to the normal ovary, and EOC patients whose tumors expressed low levels of PGR possessed significantly shorter progression-free survival than did those whose tumors expressed high levels of PGR. Multiple studies have described potential roles for the progesterone receptor in ovarian cancer, but our analysis is the first to demonstrate differential, decreased expression of PGR in tumors from patients with ovarian cancer and specifically in HGSC, in conjunction with unfavorable progression-free survival outcomes for ovarian cancer patients with low tumor expression of PGR.