Fine Deletional Mapping of Chromosome 4q22-35 Region in Oral Cancer

We analyzed loss of heterozygosity in detail of the long arm of chromosome 4 in 40 oral cancer by using 16 microsatellite markers based on the recent data from human genome sequence and defined the deletional mapping of the region with putative tumor suppressor genes. Our data revealed two distinct commonly deleted regions around the markers D4S2623 and D4S1644 with an allelic deletion of 44% and 39%, respectively. Additional mapping and use of the markers near one of these hot spots narrowed down the minimally deleted region about 1.5 Mbp around the marker, D4S2623. Caspase 6 is just localized 280 kb distant from the marker, D4S2623. Fine mapping of this region with possible tumor suppressor gene suggest caspase 6 as a putative tumor suppressor gene. Further molecular analysis of caspase 6 should be performed to clarify its role in oral carcinogenesis.