Clinical significance of microsatellite instability in sporadic epithelial ovarian tumor

Abstract

5128 Background: The microsatellite instability (MSI), first identified in colorectal cancers in 1993, has been recognized in other malignancies. In HNPCC and associated malignancies demonstrating MSI have a unique histological appearance, improved prognosis and altered response to chemotherapy. Although the panel of markers for ovarian tumors is not known, we evaluated epithelial ovarian tumors for MSI based on the 14 markers including NCI recommendations. Moreover, MSI expression according to histologic subtype and stage were evaluated. Methods: Twenty-one cases of borderline ovarian carcinoma and 25 cases of ovarian carcinoma were analyzed for MSI using frozen specimens fluorescence technology and 14 selected markers (BAT25, BAT26, D5S346, D2S123, D17S250, NME1, D3S1611, D10S197, D11S904, D13S175, DXS981, DXS6800, DXS6807, AR). According to the histologic subtype, total 46 cases were consisted of 10 cases of serous, 26 cases of mucinous, and 10 cases of endometrioid tumor. Twenty-five ovarian carcinomas were divided to 9 cases of stage I, 3 cases of stage II, and 13 cases of stage III. The interpretation of MSI included MSI-H and MSI-L. Results: On the basis of the NCI markers, 2 (9.5%) borderline ovarian carcinomas demonstrated MSI and 2 (8%) ovarian carcinomas had MSI. When all of the 14 markers were considered, 3 (14.2%) borderline ovarian carcinomas and 4 (16%) ovarian carcinomas showed MSI. The MSI was demonstrated in 3 (30%) serous, 2 (12%) mucinous, and 1 (10%) endometrioid subtype, respectively. One (11%) case of stage I and 3 (23%) cases of stage III had MSI. Conclusions: In our study, the detection of MSI using 14 markers including NCI recommendations found to have little contribution to reveal the carcinogenesis of sporadic epithelial ovarian tumor. Further studies based on another MSI markers are necessary to correlate these markers with the carcinogenesis of epithelial ovarian tumor. No significant financial relationships to disclose.