FREQUENT LOSS OF HETEROZYGOSITY ON CHROMOSOME-9 IN ADENOCARCINOMA ANDSQUAMOUS-CELL CARCINOMA OF THE ESOPHAGUS

Loss of heterozygosity (LOH) affecting chromosome 9p has been shown to occur frequently in head and neck cancer, glioma, mesothelioma, melan oma, lung cancer, and numerous other tumor types. Chromosome 9p is the refore presumed to contain a tumor suppressor gene or genes. Since eso phageal cancer shares characteristics with some of the above tumor typ es, we performed a detailed examination of 60 patients with squamous c ell carcinoma or adenocarcinoma of the esophagus for LOH at loci D9S16 2, IFNA, D9S171, D9S126 D9S104, D9S165, and D9S163. Multiplex polymera se chain reactions were performed with the inclusion of one radiolabel ed nucleotide, and products were electrophoresed on denaturing polyacr ylamide gels. Thirty-six of the 60 patients (60%) exhibited LOH at one or more loci on chromosome 9p. Eight of 17 patients (47%) with adenoc arcinoma manifested LOH, while 28 of 43 (65%) with squamous cell carci noma showed LOH. LOH was most frequent at loci D9S171 (19 of 23, or 83 %) and D9S165 (24 of 32, or 75%). These data support the hypothesis th at a tumor suppressor gene or genes located on this portion of chromos ome 9p exert(s) an effect on esophageal cancer development.