INTRATUMORAL GENETIC-HETEROGENEITY IN PRIMARY HEAD AND NECK SQUAMOUS CARCINOMA USING MICROSATELLITE MARKERS

We investigated intratumoral genetic variability using 13 of the most frequently altered microsatellite loci in primary head and neck squamo us carcinoma to determine the extent and the im plication of this feat ure on the interpretation of the genetic analysis of these tumors. DNA extracted from four spatially different samples of 17 prospectively r esected specimens, in addition to matching normal mucosa, was tested, Overall, the highest incidence of loss of heterozygosity was noted at chromosomes 3p and 9p loci (70% in each). Chromosomes 8p and 17p loci showed 35% and 40% loss of heterozygosity, respectively. Loss of heter ozygosity was homogeneously manifested in all different samples of tum ors with these alterations. Microsatellite instability was noted in tw o (17%) tumors, one of which showed intratumoral heterogeneity. Our st udy indicates that single sample analysis may reflect the genetic alte rations in a given primary head and neck squamous carcinoma using thes e markers.