No evidence of Peutz-Jeghers syndrome gene LKB1 involvement in left-sided colorectal carcinomas

LKB1 serine/threonine kinase is a gene for Peutz-Jeghers cancer predisposit ion syndrome, Most studies have detected a low frequency of LKB1 defects in sporadic cancer. A notable exception is a recent report describing frequen t, mostly missense type, LKB1 mutations in Korean distal colorectal tumors. To clarify the role of LKB1 in colon cancer, we scrutinized 50 left-sided Korean and Finnish specimens. No somatic mutations were found. The seven Ko rean somatic missense mutations reported previously were functionally analy zed, and five were found not to alter LKB1 kinase activity. One of these ch anges was found to be a germ-line polymorphism, LKB1 involvement in distal colorectal cancer is not common.