In particular, constitutively active mutations of the K-ras gene are observed in almost all pancreatic cancers (>95%) and are found in 36–87% of pancreatic intraepithelial neoplasia (PanIN) tissues, which are considered to be the precancerous lesions of the pancreatic cancer6, 7, 8. This evidence concerns the gene KRAS and familial pancreatic carcinoma.