KRAS and nonpapillary renal cell carcinoma: While some studies outlined a different incidence of mutations among the RAS isoforms in RCC samples, with 0–16% of KRAS mutation and very rare events in NRAS and HRAS [105], others did not detect any mutation of KRAS, such as BRAF, neither in primary nor in metastatic ccRCC or PRCC [106].