Ovarian Clear Cell Carcinoma Sub-Typing by ARID1A Expression

PURPOSE: Loss of AT-rich DNA-interacting domain 1A (ARID1A) has been identified as a driving mutation of ovarian clear cell carcinoma (O-CCC), a triple-negative ovarian cancer that is intermediary between serous and endometrioid subtypes, in regards to molecular and clinical behaviors. However, about half of O-CCCs still express BAF250a, the protein encoded by ARID1A. Herein, we aimed to identify signatures of ARID1A-positive O-CCC in comparison with its ARID1A-negative counterpart. MATERIALS AND METHODS: Seventy cases of O-CCC were included in this study. Histologic grades and patterns of primary tumor, molecular marker immunohistochemistry profiles, and clinical outcomes were analyzed. RESULTS: Forty-eight (69%) O-CCCs did not express BAF250a, which were designated as "ARID1A-negative." The other 22 (31%) O-CCCs were designated as "ARID1A-positive." ARID1A-positive tumors were more likely to be histologically of high grades (41% vs. 10%, p=0.003), ERβ-positive (45% vs. 17%, p=0.011), and less likely to be HNF1β-positive (77% vs. 96%, p=0.016) and E-cadherin-positive (59% vs. 83%, p=0.028) than ARID1A-negative tumors. Patient age, parity, tumor stage were not significantly different in between the two groups. Cancer-specific survival was not significantly different either. CONCLUSION: We classified O-CCCs according to ARID1A expression status. ARID1A-positive O-CCCs exhibited distinct immunohistochemical features from ARID1A-negative tumors, suggesting a different underlying molecular event during carcinogenesis.

Lack of prognostic significance of HER-2/neu in early epithelial ovarian cancer.

A total of 74 patients with apparent early stage epithelial ovarian cancer who underwent exploratory laparotomy at King Chulalongkorn Memorial Hospital or other hospitals and were referred for further treatment, were evaluated. Formalin fixed paraffin-embedded ovarian tissue specimens were collected and immuno-stained with HER-2/neu antibodies for comparison with clinicopathologic data after median follow up of 46 months (range 3 - 83 months). The prevalence of HER-2/neu overexpression in these patients was 10.2%. No significant correlation between HER-2/neu overexpression and clinicopathological parameters (stage, ascites, capsular rupture, capsular adherence, histological subtype and histological grade) was found. Disease free survival and overall survival did not statistically differ between those with lesions positive or negative for HER-2/neu overexpression.