Background & aims: The existence of an unknown tumor-suppressor gene on 5q for esophageal carcinoma other than the APC gene has been suggested. The location of the putative tumor-suppressor gene on 5q, distinct from the APC gene, was examined.
Methods: Sixty-one primary esophageal carcinomas were examined for nine microsatellite loci by the polymerase chain reaction followed by polyacrylamide gel electorophoresis. Loss of heterozygosity at the APC gene locus also was examined by the polymerase chain reaction-restriction fragment length polymorphisms.
Results: Thirty-five of 61 esophageal carcinomas (57%) showed loss of heterozygosity at single or multiple loci on 5q, and the smallest common deleted region was identified at 5q31.1, the location of the IRF-1 gene locus. All tumors showing loss of heterozygosity at the APC gene locus showed complete or large interstitial deletions on 5q.
Conclusions: Deletion at the APC gene locus may just be the result of large deletions on 5q and may not be important in esophageal carcinogenesis, and the IRF-1 gene or other gene(s) on 5q31.1 may be the true target of frequent deletions on 5q that may play an important role in the pathogenesis of the majority of esophageal carcinomas.