KRAS and lung adenocarcinoma: Unfortunately, in approximately 50% of adenocarcinoma and for those harbouring K-RAS mutations, the most frequent mutation in Caucasian lung adenocarcinoma, so far no specific drug demonstrated efficacy.The rat sarcoma (RAS) genes, including H-RAS, K-RAS, and N-RAS, encode a family of proteins regulating cell growth, differentiation, and apoptosis.