Clinical Value of MLPA for Prognostic Assessment of Chromosomal Rearrangements and DNA Methylation in Uveal Melanoma

Uveal melanoma (UM) is the most prevalent primary intraocular malignancy in adults, with prognosis significantly influenced by genetic and epigenetic factors. Reliable and cost-effective methods to detect chromosomal aberrations and DNA methylation changes are essential for improving prognostication and informing treatment strategies in UM. This study evaluated the effectiveness of multiplex ligation-dependent probe amplification (MLPA) in detecting UM-specific copy number variations (CNVs) and promoter methylation changes across 25 tumor suppressor genes (TSGs).

DNA from 58 UM tissues was analyzed with the SALSA MLPA Probemix P027 Uveal melanoma kit, and a subset of 18 samples was further assessed using the SALSA MLPA Probemix ME002-C1 Tumour suppressor mix 2 kit to identify key CNVs and methylation alterations linked to poor prognosis. Validation was carried out with a high-resolution comparative genomic hybridization (CGH) array on 10 samples and the Illumina Infinium Methylation EPIC v1.0 BeadChip array on 25 samples.

Our findings indicate that MLPA is a versatile and robust method for detecting CNVs, showing strong correlations with CGH data and highlighting specific CNV patterns linked to clinical outcomes in UM. However, the ME002-C1 kit showed limited utility for comprehensive methylation analysis, as differential methylation was not observed in the studied TSG loci.

Although MLPA effectively identifies CNVs relevant to UM prognosis, integrating additional methylation-specific approaches could broaden the scope of DNA methylation analysis, offering a more comprehensive molecular understanding of UM that may enhance prognostication and personalized treatment.