Gupta S, Swanson AA, Chen YB, et al. - Subtype-specific consecutively diagnosed renal cell neoplasms were recruited in a study by the researchers in order to determine the incidence of succinate dehydrogenase (SDH) and fumarate hydratase—deficient renal cell carcinoma on the basis of the immunohistochemical screening with SDHA/SDHB and fumarate hydratase (FH)/S-(2-succino)-cysteine (2SC). In three of 273 tumors originally diagnosed as oncocytomas, the loss of SDHA/SDHB was noted. Diffuse nuclear and cytoplasmic 2SC staining, with retained FH expression was observed in one case (suggestive of dysfunctional FH protein), whereas absent FH was discovered in 3 cases. In 273 cases originally diagnosed as oncocytomas, no aberrant FH/2SC expression was remarked. SDH-deficient renal cell carcinomas (RCC) were recognized only in the cases originally diagnosed as oncocytomas, while FH-deficient RCCs were distinguished in the papillary and unclassified RCC cohorts. Therefore, these conclusions can aid in guiding immunohistochemistry-based screening approaches for these tumors.