These features can be used in the differential diagnosis from clear cell renal cell carcinoma which displays a higher positivity rate for RCC-Ma but is usually negative for CK7 and parafibromin, as well as from papillary renal cell carcinomas, which are typically positive for CK7 and RCC-Ma but negative for parafibromin [31]. This evidence concerns the gene KRT7 and renal cell carcinoma.