Abstract: Objective To compare the efficacy of fluorescence in situ hybridization (FISH) and multiplex ligation-dependent probe amplification (MLPA) for the detection of chromosome 3 aberration in uveal melanoma. Design Experimental study. Participants 33 eyeball specimen of uveal melanoma patients who were treated with primary enucleation without previous plaque radiotherapy in Beijing Tongren Hospital during 2019. Methods Clinical histopathologic characteristics of these patients were retrospectively analyzed. The chromosome copy numbers of formalin fixed paraffin embedding (FFPE) tumors of 33 eyeballs were detected using FISH and MLPA respectively and then the results were compared. The correlation between monosomy 3 and clinical histopathologic features was analyzed. Main Outcome Measures Chromosome 3 copy number, age, gender, tumor location, tumor largest basement diameter, tumor cell type. Results The proportion of monosomy 3 in tumor detected by FISH was 33.3% and 36.4% by MLPA. In one patient, FISH detected dysomy 3 while MLPA detected monosomy 3. The overall compliance rate of FISH and MLPA was 97.0%. The proportion of monosomy was 66.7% (6/9) in ciliary body involvement group and 25.0% (6/24) in non-ciliary body involvement group (P=0.044). The proportion of monosomy 3 was 50.0% (8/16) in epithelioid cell type group and 23.5% (4/17) in the non-epithelioid cell type group (P=0.157). Conclusion Monosomy 3 was 36.4% in uveal melanoma. Both FISH and MLPA can be used to detect chromosome 3 aberration in FFPE samples of uveal melanoma. The sensitivity of MLPA detection is slightly higher than that of FISH.

Key words: uveal melanoma, metastasis, monosomy 3, FISH, MLPA