Comparison of Gene Expression Profiling and Chromosome 3 Analysis by Fluorescent in situ Hybridization and Multiplex Ligation Probe Amplification in Fine-Needle Aspiration Biopsy Specimens of Uveal Melanoma

Abstract

Purpose: The aim of this paper was to assess the concordance between results of DecisionDx-UM specific gene expression profiling (GEP) and fluorescence in situ hybridization (FISH) for chromosome 3 analysis, and between DecisionDx-UM GEP and multiplex ligation probe amplification (MLPA) in uveal melanoma undergoing intraoperative fine-needle aspiration biopsy (FNAB) for metastatic prognostication during brachytherapy. Methods: We retrospectively reviewed consecutive patients diagnosed with posterior uveal melanoma who underwent intraoperative FNAB prior to placement of an iodine-125 radioactive plaque between 2012 and 2014. Two cohorts of patients were identified: Cohort 1 - tumors in which both GEP and FISH results were obtained, and Cohort 2 - tumors in which both GEP and MLPA results were obtained. Results: Forty-four patients were identified for Cohort 1. FISH and GEP results were discordant in 7 tumors (15.9%). Forty-three patients were identified for Cohort 2. MLPA and GEP were discordant in 7 tumors (16.3%). Conclusions: Discordance between GEP and chromosome 3 status by FISH and MLPA occurred in our series at a rate of 15.9 and 16.3%, respectively. Caution must be advised when counseling a patient with a good-prognosis GEP "Class 1" result that the uveal tumor may actually harbor monosomy 3, which is associated with a poor prognosis for metastasis in nearly 20% of the patients.