17P ALLELIC LOSSES IN DIPLOID-CELLS OF PATIENTS WITH BARRETTS-ESOPHAGUS WHO DEVELOP ANEUPLOIDY

Inactivation of the p53 gene, located on chromosome 17p, leads to gene tic instability and aneuploidy in vitro. Aneuploid cell populations fr om Barrett's adenocarcinomas have a high prevalence of 17p allelic los ses, and there is substantial evidence that the target of these losses is the p53 gene. If 17p allelic losses lead to aneuploidy in Barrett' s esophagus, then they should be present in diploid cells from patient s who develop aneuploidy. We detected 17p allelic losses in diploid ce lls from 10 of 11 patients (91%) with Barrett's esophagus who develope d aneuploid cell populations. Our data strongly suggest that 17p allel ic losses precede the development of aneuploidy during neoplastic prog ression in Barrett's esophagus in vivo and, therefore, support in vitr o evidence for the role of p53 in genetic instability.