A defined region of loss of heterozygosity at 11q23 in cutaneous malignant melanoma.

Karyotypic and molecular data indicate that genetic alterations of the long arm of chromosome 11 (11q) may be involved in malignant melanoma. To test this we analyzed 5 polymorphic microsatellite repeats on 11q using a PCR-based assay for loss of heterozygosity in normal and tumor tissues from 24 individuals with cutaneous malignant melanoma of various stages. Our findings indicate that a tumor suppressor gene that plays a role in malignant melanoma is located on the long arm of chromosome 11, likely within a 51 cM region at 11q23. Its loss appears to be a late event in tumor progression and may serve as an indicator for a less favorable clinical outcome.