Concordant chromosome 3 results in paired choroidal melanoma biopsies and subsequent tumour resection specimens

BACKGROUND/AIM: The study's aim was to compare chromosome 3 aberrations of choroidal melanoma (CM) as determined by multiplex ligation dependent probe amplification (MLPA) or microsatellite analysis (MSA) in intraocular tumour biopsies with those results obtained from subsequent endoresection/enucleation of the same CM. METHODS: A retrospective cohort of 28 patients with CM seen between 2007 and 2014 at the Liverpool Ocular Oncology Centre was analysed. Prognostic genetic testing, for chromosome 3 status, was performed on all tumour specimens, either by MLPA or MSA, depending on DNA yield. In nine cases genetic testing was performed on a sample taken after radiotherapy; four of these had genetic information pre- and post-radiotherapy. RESULTS: Fourteen biopsy specimens were analysed by MLPA and 14 by MSA. Twenty-seven endoresection or enucleation specimens were analysed by MLPA, and a single enucleation specimen by MSA. Chromosome 3 data showed prognostic concordance for the patient-matched samples in all 28 cases including 4 cases where samples were taken pre pre- and post radiotherapy. Thirteen cases were classified as monosomy 3 and 12 as disomy 3. Two cases had a loss of chromosome arm 3q in both samples and a single case showed loss of 3p in the biopsy sample with complete monosomy 3 in the subsequent enucleation sample taken 5 months later. CONCLUSIONS: Intraocular biopsy of CM yields similar prognostic information to larger surgical specimens. Initial evidence, that genetic testing can be successfully conducted post radiotherapy, is also provided. TRIAL REGISTRATION NUMBER: NITRO trial, ISRCTN35236442.