Differential expression of ABCF2 protein among different histologic types of epithelial ovarian cancer and in clear cell adenocarcinomas of different organs

Previously, we reported that ABCF2 protein expression is higher in clear cell than serous histotype of ovarian adenocarcinomas and that its expression correlates with chemoresponse in patients with clear cell ovarian cancer. In this study, we examined ABCF2 protein expression in mucinous, endometrioid, and poorly differentiated type of ovarian adenocarcinomas. In addition, ABCF2 expression was evaluated in clear cell adenocarcinomas derived from different organs. A total of 335 epithelial ovarian cancers, 23 clear cell adenocarcinomas of uterine corpus, and 34 clear cell adenocarcinomas of kidney were included in this study. ABCF2 protein expression was determined by immunohistochemistry. The results showed that cytoplasmic ABCF2 expression was significantly higher in clear cell-type ovarian cancer specimens compared with other types (P < .0001). There was a close relationship between nuclear ABCF2 expression levels and age of patients with clear cell ovarian cancer. Multivariate logistic regression model also demonstrated that cytoplasmic ABCF2 expression was associated with clear cell histology (odds ratio, 5.557; 95% confidence interval, 2.694-11.462; P < .0001). In addition, both clear cell adenocarcinomas of the ovary and the uterine corpus showed significantly higher levels of ABCF2 expression, compared with those of the clear cell adenocarcinoma of the kidney (P < .0001). These data suggest that ABCF2 protein may be a candidate marker for clear cell adenocarcinomas of the ovary and the uterine corpus and may be important for the pathogenesis of these diseases.