Association of GNAQ Mutation in Choroidal Melanoma

Abstract

Purpose: : Somatic mutations of GNAQ, the heterotrimeric G protein alpha subunit, are increased in patients with choroidal melanoma. Specifically, the mutation occurring in codon 209 in the ras-like domain, results in constitutive activation. The purpose of this study was to determine if genetic screening for the GNAQ mutation via blood sample could be used to predict patients more likely to develop choroidal melanoma.

Methods: : Twelve patients diagnosed with choroidal melanoma were enrolled and genotyped for the GNAQ mutation. Recruited patients already had a diagnosis of choroidal melanoma and were seen in follow up between July 2009 and September 2009. The patients were classified into groups based on the size of their tumor. A large tumor was defined as >16mm in basal diameter and/or >10mm in apical height. A medium tumor was 6mm to 16mm in basal diameter and/or 2.5mm to 10mm apical height. A small tumor was 4.0mm to 6.0mm in basal diameter and/or 1.0-2.4mm in apical height.

Results: : Twelve patients with a mean age of 60.5 years, (5 female, 7 male) with the diagnosis of choroidal melanoma were enrolled. Nine of patients had the choroidal melanoma in the right eye, 3 patient had developed the tumor in his left eye; no patients had bilateral melanoma. Seven patients were classified with a large choroidal melanoma, five with a medium sized tumor. No patients had a small tumor.

Conclusions: : The GNAQ mutation analysis is currently underway in twelve patients diagnosed with choroidal melanoma. These results will demonstrate whether or not genetic screening for the GNAQ mutation is a viable option for patients concerned about the development of choroidal melanoma.

Keywords: genetics • melanoma • choroid