Introduction: Distinguishing primary ovarian clear cell carcinoma (CCC) from other tumors with clear cell features can be challenging. Hepatocyte nuclear factor-1β (HNF-1β) is a sensitive and specific marker for ovarian CCC. Immunohistochemical studies have shown HNF-1β positivity in a substantial proportion of clear cell renal cell carcinoma (RCC), hepatocellular carcinomas, and clear cell pancreatic adenocarcinoma. This study was designed to evaluate the role of HNF-1β in differentiating ovarian CCC from metastatic RCC and urothelial carcinoma (UC) with clear cell features.
Materials and methods: Formalin-fixed paraffin-embedded tissue microarrays of 103 clear cell RCC, 8 UC with clear cell features, and 15 ovarian CCC were studied using an HNF-1β antibody. Nuclear staining intensity and percentage of positively stained cells were assessed and scored from 0 to 3. Percentage of positive staining was scored based on the proportion of tumor cells stained.
Results: Sixty-three of 103 (61.2%) of clear cell RCC were positive for HNF-1β. Staining intensity was weak in 32 of 103 cases (31.6%), moderate in 21 of 103 cases (20.4%), and strong in 10 to 103 cases (9.7%).Six of 8 (75%) UC with clear cell features showed positive staining predominantly in clear cell areas.All 15 cases of ovarian CCC were positive for HNF-1β.
Discussion: Overall 61.2% of clear cell RCC and 75% of UC were immunopositive with HNF-1β in our study. HNF-1β has a limited utility in differentiating CCC of the genitourinary system from an ovarian primary.