Alterations of p53 and k-ras genes in human colorectal-cancer with ulcerative-colitis

Using polymerase chain reaction and single strand conformation polymorphism assay, we examined genetic alterations of p53 and K-ras genes in multiple lesions of colorectal cancers that developed in three patients with ulcerative colitis. p53 gene mutations were found in two lesions and a K-ms gene mutation at codon 12 was found only in one. Neither was found in non-cancerous lesions. The results indicate that mutation of both genes may not be so frequent among Japanese patients. They were found only in very few cancerous lesions of each patient. Therefore, it is possible that the oncogenic process in each lesion is a consequence of rather independent events. Our preliminary results suggest the potential usefulness of CD44 variant forms as markers for dysplastic and cancerous tissues in ulcerative colitis.