DETAILED DELETION MAPPING IN SQUAMOUS-CELL CARCINOMAS OF THE ESOPHAGUS NARROWS A REGION CONTAINING A PUTATIVE TUMOR-SUPPRESSOR GENE TO ABOUT 200 KILOBASES ON DISTAL CHROMOSOME 9Q(1)

We previously reported definition of a region containing a putative tu mor suppressor gene for esophageal squamous cell carcinoma within an s imilar to 4-cM genomic segment at 9q31-q32. We have investigated this region further using six new microsatellite markers isolated from yeas t artificial chromosome clones covering the deleted region and have na rrowly defined the commonly deleted region to a segment between two lo ci, KM9.1 and D9S177, On the basis of the contig map of cosmid and yea st artificial chromosome clones, we estimate the physical size of the region of interest to be about 200 kb, Because the distal 9q region al so has been implicated as the site of a tumor suppressor gene(s) relat ed to squamous cell carcinomas of other tissues, our map provides usef ul information for attempts to identify a common gene for carcinomas o f this cell type.