BSND and kidney oncocytoma: We next examined the expression status of BSND and ATP6V1G3 in renal oncocytoma, since this benign tumor often shares common morphological and immunophenotypic features with chromophobe RCC.30,31 Immunohistochemical analysis for the BSND and ATP6V1G3 proteins revealed strong diffuse positivity for both in most of the renal oncocytoma specimens (13/14 cases, 92.9%, for both proteins) (Figure 2M–O and Table 3), suggesting that BSND and ATP6V1G3 are immunohistochemical markers for renal oncocytoma as well as chromophobe RCC.