Hormone receptor expression patterns define clinically meaningful subgroups of endometrioid ovarian carcinoma

Background Numerous studies have investigated the association between hormone receptor expression and clinical outcome in ovarian carcinoma (OC); however, these have largely focussed on serous OCs, with few studies reporting specifically on endometrioid OCs (EnOC). Where analyses have been stratified by histotype, expression has been assessed using the percentage of positive tumor cells, without accounting for nuclear expression intensity. Methods Here we assess the expression levels of progesterone receptor (PR), estrogen receptor alpha (ER) and androgen receptor (AR) using histoscore – a nuclear scoring method incorporating both proportion of positive cells and the intensity of nuclear staining – across a cohort of 107 WT1 negative EnOCs. Results Hierarchical clustering by PR, ER and AR histoscores identified four EnOC subgroups (PR+/ER+, PR+/ER−, PR−/ER+ and PR−/ER−). EnOC patients in the PR+/ER+ and PR+/ER− groups displayed favorable outcome (multivariable HR for disease-specific survival 0.05 [0.01–0.35] and 0.05 [0.00–0.51]) compared to the PR−/ER+ group. Ten-year survival for stage II PRhigh and PRlow cases was 94.1% and 42.4%. ERhigh EnOC patients (PR+/ER+, PR−/ER+) had higher body mass index compared to ERlow cases (P = 0.015) and high grade serous OC patients (P
Highlights • We identify four subgroups of endometrioid ovarian carcinoma (EnOC) defined by hormone receptor expression patterns. • EnOC patients in the PRhigh (PR+/ER+, PR+/ER−) groups demonstrate markedly favorable outcome. • Stage II EnOC patients in the PRhigh groups display a ten-year survival of approximately 95%. • ERhigh (PR+/ER+, PR−/ER+) EnOC patients had a higher body mass index vs ERlow cases and high grade serous carcinoma patients.