Aneuploidy in Uveal Melanoma Is an Indicator of Poor Prognosis

Abstract

Purpose: : Previously, it has been shown that numerical chromosomal changes in patients with uveal melanoma are associated with disease progression. The present study evaluates clinical and genetic parameters of choroidal melanomas with the unusual chromosomal aberration gain of part of the short arm of chromosome 1.

Methods: : 122 uveal melanomas were analyzed for numerical changes in chromosomes 1, 3, 6, and 8, using chromosome analysis and fluorescent in situ hybridization (FISH). To delineate the critical region on chromosome 1p, additional FISH experiments were performed on tumors with 3 or more copies of chromosome 1p36.33. The overall ploidy of these particular tumors was compared with other tumors in our database.

Results: : 10/122 melanomas showed 3 or more signals for chromosome 1p36.33. The average largest tumor diameter was 16mm (range 7–19mm) and 8/10 tumors were composed of epitheloid or mixed cells. 8/10 tumors with 3 or 4 signals on chromosome 1p had an overall aneuploid character (triploid or tetraploid, respectively). The additional FISH probes used for the critical region on chromosome 1p36 could not define the critical region. The aneuploidy in uveal melanomas corresponded with progressive disease compared to euploidy (p=0.0001): a mean survival of 31 months with 8/10 patients having metastatic disease (within 2–67 months). Only 2/10 patients did not show metastases during at least 24 months of follow–up (range 24–97 months). One of these patients (97 months post enucleation) had a pure gain on chromosome 1p and could be considered as a different entity.

Conclusions: : Gain of chromosome 1p is suggested to be indicative of a particular subset of uveal melanomas with gross aneuploidy and extremely poor survival. The role of loss and gain of the short arm of chromosome 1 in uveal melanomas will be subject to future investigation.

Keywords: melanoma • genetics • oncology