Evaluation of overexpression of HER2/neu in primary uterine, ovarian, and peritoneal papillary serous carcinoma.

Abstract

e15512 Background: Primary uterine papillary serous carcinoma (UPSC), ovarian papillary serous carcinoma (OPSC), and peritoneal papillary serous carcinoma (PPSC) share histologic features and are biologically more aggressive than other mullerian tumors. HER2/neu (c-erbB-2) is a proto-oncogene identified on chromosome 17 at q21which is responsible for unregulated cell growth, differentiation, and prolonged survival. The purpose of this study was to compare differences in HER2/neu overexpression in patients with primary UPSC, OPSC, and PPSC. Methods: After IRB approval was obtained, H&E stained slides and formalin-fixed paraffin-embedded blocks of the tumors were obtained from the Department of Pathology. HER2/neu overexpression in the tumor was evaluated by immunohistochemistry utilizing FDA approved IHC using the Hercep Test with appropriate controls. Scores of 0 to 1+ were considered negative and scores of 2+ to 3+ considered positive (weakly and strongly positive, respectively). Clinical data including age at diagnosis, FIGO stage and tumor grade was abstracted from the medical records; statistical methods included t-test, Chi-Square, attributable risk and relative risk determinations. Results: A total of 55 cases were analyzed, and included UPSC (26), OPSC (25), and PPSC (4). The patients with positive compared with negative HER2/neu expression were significantly older (69 ± 10.6 vs. 59.4 ± 5.9 years, p < 0.02). HER2/neu overexpression was observed more frequently in UPSC (13, 50%) than in OPSC (4, 16%, p < 0.05). The relative risk for HER2/neu overexpression in UPSC was found to be 3.1- fold higher than that for OPSC, and the attributable risk was 34%. No significant correlation was found by FIGO stage or tumor grade (p < 0.5). Of note, none of the PPSC tumors exhibited HER2/neu overexpression. Conclusions: HER2/neu overexpression is linked to older patients and to UPSC histology. Further investigation of HER2/neu overexpression in primary UPSC and as a potential marker to distinguish UPSC from similar tumors is warranted. Utilizing FISH is the necessary next step, in order to confirm gene amplification in these tumors if anti-HER2 antibody therapy would be a possible treatment option in these tumors. No significant financial relationships to disclose.