Melanoma, Uveal, Susceptibility To, 2

Uveal melanoma (155720) is the most common primary intraocular malignancy. Monosomy 3, which is an unusual finding in most tumors, is present in approximately 50% of uveal melanomas and is significantly correlated with metastatic disease. To obtain positional information on putative tumor suppressor genes on chromosome 3, Tschentscher et al. (2001) investigated tumors from 333 patients by comparative genomic hybridization, microsatellite analysis, or conventional karyotype analysis. A partial deletion of the long arm was found in 8 tumors, and the smallest region of deletion overlap (SRO) spanned 3q24-q26. They found 6 tumors with a partial deletion of the short arm and defined a second SRO of about 2.5 Mb in 3p25. This SRO did not overlap with the von Hippel-Lindau disease gene (608537). Tschentscher et al. (2001) interpreted their findings as suggesting a role for 2 tumor suppressor genes in metastasizing uveal melanoma: one on 3q, here designated UVM1 (606660), and a second on 3p25, here designated UVM2. The involvement of 2 tumor suppressor genes may explain the loss of an entire chromosome 3 in metastatic uveal melanomas.

Parrella et al. (2003) mapped both arms of chromosome 3 in 21 uveal melanomas that did not show monosomy 3 in previous allelotype studies. DNA was isolated from microdissected paraffin sections of posterior uveal melanoma treated by enucleation from 1993 to 1998 and archived by the Eye Pathology Laboratory of the Wilmer Ophthalmologic Institute, Johns Hopkins. In an initial screening, 14 microsatellite markers on 3p and 13 on 3q were used. Loss of heterozygosity for at least 1 marker was found in 9 of 21 tumors (43%) on 3p and 8 of 21 tumors (38%) on 3q. Two common regions of allelic loss on 3p were further mapped with an additional 14 microsatellite markers. A 1.4-Mb minimal region of allelic loss was identified between microsatellite markers D3S3610 and D3S1554 on 3p25.2-p25.1. Ten tumors had allelic loss in this region; 2 of these tumors had corresponding putative homozygous deletions.