MLH1 and colorectal neoplasm: Of 656 tumours for which the other molecular alterations, i.e. mutations in the APC and K-ras genes and hMLH1 expression, were all successfully and completely analysed, 103 colorectal tumours did not harbour a truncating or missense APC mutation, an activating K-ras mutation or showed lack of hMLH1 expression, as depicted in figure 1.