LOSS OF HETEROZYGOSITY FOR 10Q22-10QTER IN MALIGNANT-MELANOMA PROGRESSION

Karyotypic and molecular data indicate that genetic events involving t he chromosome region 10q22-10qter may be related to tumorigenesis in m alignant melanoma. To test this we analyzed 10 polymorphic microsatell ite repeats in the region 10q22-qter, using a polymerase chain reactio n-based assay for loss of heterozygosity and DNA isolated from normal and tumor tissue from 26 individuals with malignant melanoma. The samp les included 19 paired normal and malignant tissues representing vario us stages of melanoma as well as 7 cases in which samples from at leas t 2 different points in time during tumor progression were available. Our findings indicate that loss of heterozygosity of 10q22-10qter is a frequent event, that the observed loss of heterozygosity does not res ult from whole chromosome loss, and that it is associated with tumor p rogression. Finally, the appearance of new alleles in two of the tumor s may indicate the involvement of DNA replication errors in melanoma a nalogous to such events in other tumor types.