Validation of microarray data. Short-term cultures of CM cells generated from neoplastic lesions of 45 stage IIIC melanoma patients were evaluated for WNT10B, TUB, ALOX12B and SLC6A11 methylation and mRNA expression by qMSP and qRT-PCR analyses, respectively. All cells were analyzed at 6th in vitro passage. For each gene, the % of methylation measured by qMSP was defined as the ratio between methylated gene molecules and the sum of methylated and unmethylated gene molecules. Level of gene expression is reported as number of molecules of the target gene normalized to the number of molecules of the housekeeping gene β-actin. Panel a, Correlation between % methylation defined by qMSP and β-values defined by the Illumina HumanMethylation27 Bead-Chip assay was evaluated for each gene through the Spearman’s rank correlation test. Reported P values are two sided. Panel b, Correlation between methylation and mRNA expression was evaluated for each gene by Spearman’s rank correlation test. Reported P values are two sided.