[Clinical significance of genetic instability in gastrointestinal cancers]

We reviewed the clinical significance of genetic instability or replication error (RER) in human gastrointestinal carcinomas. The RER positive tumors are seen in about 10-30% of these carcinomas. The RER positive esophageal carcinomas tend to show unusual histologic subtypes such as adenocarcinoma or small cell carcinoma. The RER positive gastric carcinomas show no specific characteristics in our study while several investigators describe the high frequency of poorly differentiated adenocarcinomas of the higher frequency of advanced carcinomas. The RER positive colorectal carcinomas show a tendency to show poorly differentiation to occur in the proximal colon, to have no lymph node metastasis and to show good prognosis. Several candidate genes that may correlate with RER are shown.