Immunohistochemical analysis of clear cell carcinoma of the gynecologic tract.

Clear cell carcinoma of the gynecologic tract has been defined in terms of its clinical and histologic features; however, its immunophenotypic profile has not been fully characterized. Seventeen cases of primary clear cell carcinoma from various sites within the female genital tract (11 ovary, 5 uterus, 1 vagina) were analyzed by immunohistochemistry. These tumors were assessed for the expression of cytokeratin 7 (CK7), cytokeratin 20 (CK20), low and high molecular weight cytokeratin, (CAM5.2 and 34 beta E12, respectively), carcinoembryonic antigen (CEA), Leu-M1, vimentin, estrogen receptor (ER), progesterone receptor (PR), bcl-2, p53, HER-2/neu, and CA-125. The characteristic immunoprofile for all sites was positivity for CK7, CAM5.2, 34 beta E12, CEA, Leu-M1, vimentin, bcl-2, p53, and CA-125; variably positivity for ER and HER-2/neu; and negativity for CK20 and PR. For comparison, two cases of urologic clear cell carcinoma (1 bladder, 1 urethra) were also studied, and their profile was found to be similar to the gynecologic cases. Aside from minor differences, clear cell carcinoma appears to have the same immunophenotype regardless of whether it originates in the endometrium, ovary, or genitourinary tract. Much of its profile is similar to other gynecologic adenocarcinomas, but some of the markers studied may be useful in the differential diagnosis of this tumor.