With respect to tumor subtypes, small bowel cancer (41.8%, 51/122), cholangiocarcinoma (22.6%, 125/553), sarcomatoid carcinoma of the lung (SARCL) (17.0%, 9/53), clear cell ovarian cancer (CCOV) (13.5%, 5/37), and neuroendocrine tumors (NETs) (11.2%, 20/178) had the highest rates of KRAS mutation, while the mutation rates in glioma and glioblastoma were only about 2%. The gene discussed is KRAS; the disease is central nervous system cancer.