Genetic instability of microsatellite markers in region q22.3-q31 of chromosome 9 in skin squamous cell carcinomas.

Microsatellite markers assigned to chromosome 9q22.3-q31 were used in order to analyze squamous cell carcinomas from human skin. From the informative samples examined, one showed loss of heterozygosity with both microsatellite markers D9S109 and D9S180. Furthermore, in four cases with D9S109 and in one case with both microsatellite markers, genetic instability was observed in the tumors. These results are interpreted as suggestive of two distinct genetic changes associated with skin squamous cell carcinomas: Loss of a tumor suppressor gene that might relate to the observed frequent loss of a co-localized gene in basal cell carcinomas and alteration of replication/mismatch-repair factors, in similarity to the ones thought to be involved in the genetic instability detected in hereditary nonpolyposis colorectal cancer.