Immunocytochemical analysis of uterine papillary serous carcinomas for estrogen and progesterone receptors.

Uterine papillary serous carcinoma (UPSC), an aggressive histologic variant of endometrial cancer, is particularly resistant to cytotoxic chemotherapy. In reviewing a group of patients treated with cisplatin, doxorubicin, and cyclophosphamide, we were surprised to find that 90% of specimens tested by biochemical analysis were positive for estrogen receptor (ER), progesterone receptor (PR), or both. To further study receptor content and localization, we performed immunocytochemical analysis (ICA) on 29 archival UPSC specimens. In ER studies, three specimens were unevaluable because of inadequate internal controls; of the remaining 26, only two were ER positive, showing weak, focal staining. In PR studies, 18 samples had adequate controls, and all tumor specimens were receptor negative. Corresponding biochemical ER data were available for 11 cases, of which 10 were ER positive. ICA, however, showed all 10 to be negative. Biochemical PR data were available for seven samples: Six were positive. All six biochemically positive PR specimens were PR negative when analyzed by ICA. Biochemical assays for ER and PR may overestimate positivity as a result of contamination with normal tissue or the presence of receptor-positive typical endometrial adenocarcinoma in tumors of mixed histology. ICA may eliminate this problem, but it has technical limitations, especially when used for archival tissue analysis. Because urinary papillary serous carcinoma appears to be a receptor-negative tumor, further evaluation of hormonal therapy is not likely to be beneficial.