Identification of chromosomes 3, 6, and 8 aberrations in uveal melanoma by microsatellite analysis in comparison to comparative genomic hybridization

In uveal melanoma, monosomy 3 is strongly associated with metastic disease and poor prognosis. Cytogenetic analysis and comparative genomic hybridization (CGH) have been used to identify chromosomal aberrations in uveal melanoma. As these methods are costly and time consuming in routine diagnostic settings, we evaluated whether tumors with monosomy 3 can be reliably identified by microsatellite analysis (MSA). In addition, we also tested if aberrations of chromosomes 6 and 8, which have also been associated with the course of the disease, can be detected by MSA. We established a protocol for MSA of 23 markers, 3–4 on each arm of chromosomes 3, 6, and 8. Twenty tumors were analyzed by CGH and MSA, and 10 tumors were analyzed by MSA only. For chromosome 3, the results of CGH and MSA were concordant, thus indicating that the dosage of this chromosome can reliably be determined by MSA. However, MSA failed to detect copy number gains at 6p in some tumors. Moreover, despite quantitative evaluation of allele ratios, it was not possible to discern 8p losses and gains reliably. We thus conclude that while MSA can be used to determine monosomy 3 in uveal melanoma, careful interpretation of results for chromosomes 6 and 8 is recommended.