BCA2 is differentially expressed in renal oncocytoma: an analysis of 158 renal neoplasms.

The distinction between renal oncocytoma and renal cell carcinoma, especially chromophobe renal cell carcinoma and clear cell carcinoma with oncocytic features, is important due to the different biologic potentials of these tumors. RING E3 ligases have the subject of intense studies for their roles in many diseases including cancer and as potential therapeutic targets. All RING E3 ligases, including BCA2, contain a consensus protein sequence that would complex two or more zinc ions in the expressed protein. Identification of which ubiquitin ligases specifically affect distinct cellular processes is essential to the development of targeted therapeutics in these tumors. The ubiquitin-proteasome system regulates the turnover of proteins that have essential roles in the cell cycle, apoptosis, DNA damage repair, and in protein trafficking, which makes this pathway a target for oncogenic events. In this study, we investigated expression of BCA2 in renal oncocytoma and renal cell carcinoma. A total of 158 patients were included in the study. Our study has shown that 114/114 (100 %) cases of renal cell carcinoma were negative for BCA2. All 38 (100 %) cases of renal oncocytoma were positive for BCA2, and 6/6 (100 %) cases designated as oncocytic neoplasm which favor oncocytoma were also positive for BCA2. This is the first study to date evaluating the expression of BCA2 in renal oncocytoma. BCA2 could serve as a marker that may be utilized in the distinction between renal oncocytoma and its mimickers.