Cytogenetic analysis of uveal melanoma. Consistent occurrence of monosomy 3 and trisomy 8q.

Abstract

The genetic alterations associated with the pathogenesis of uveal melanoma have not been determined. To address this issue, the authors performed a prospective cytogenetic study of 35 uveal melanomas, including 23 primary untreated tumors and 12 tumors that were removed after local radiation therapy. Representative tumor tissue was processed by established methods for histopathologic and cytogenetic studies. Tumor cells were disaggregated and established in short-term culture; metaphases were prepared by standard methods for karyotypic analysis. Successful analyses were achieved in 27 of the tumor specimens, including 20 of 23 tumors not exposed to radiation and 7 of 12 tumors exposed to radiation. All of the tumors had an abnormal karyotype. Recurrent chromosomal abnormalities detected in the tumors not exposed to radiation included monosomy 3 (13 of 20), trisomy 8 or 8q (11 of 20), loss of a sex chromosome (10 of 20), and loss of 6q (8 of 20). The tumors previously exposed to radiation were characterized by more complex changes, with monosomy 3 and trisomy 8q detected in three cases each. Uveal melanoma is characterized by monosomy 3 and trisomy 8q in most cases. These findings, which are supported by data from other investigators, provide compelling evidence that loss of gene sequences on chromosome 3 and duplication of gene sequences on chromosome 8 are implicated in the genetic alterations associated with uveal melanoma and offer a basis for additional molecular genetic investigations.