PRIMARY-CANCER OF THE SMALL-INTESTINE AND MUTATIONAL ANALYSIS OF THE K-RAS AND P53 GENES

A 69-year-old woman was admitted to Hokuso Shiroi Hospital because of recurrent pain in the lower right side of the abdomen. Small-intestina l cancer was strongly suspected after fluoroscopy of the small intesti ne. Laparotomy showed advanced cancer of the ileum, of complete annula r constrictive type, 9.5 x 5 cm in size. Histologically it was moderat ely differentiated tubular adenocarcinoma. Neither visceral nor nodal metastases were found, and the patient has been well for the 20 months since surgery. The strong resemblance between the epidemiological cha racteristics of small-intestinal cancers and colorectal cancers prompt ed us to investigate the carcinogenetic mechanisms at the molecular le vel. A point mutation at codon 12 of the K-ras gene was found, while n o alterations were noted in the p53 gene, whose mutations are frequent in colon cancers. The carcinogenetic mechanisms of the small-intestin al cancer we experienced may thus differ from those of colon cancers.