KRAS and cancer: Examples are frequent somatic mutations of KRAS codons 12 and 13 [5] in various types of cancers in endodermal organs (pancreas, colon, lung, etc.), and the prevalent mutation in the kinase domain of BRAF, BRAFV600E[6], [7] in cancer cells of endodermal (thyroid, colon) and ectodermal (melanoma) tissues.