Kaplan-Meier analysis of stage IIIC CM patients survival according to genome-wide methylation profiles. Genome-wide DNA methylation profile was evaluated by Illumina HumanMethylation27 Bead-Chip whole-genome assay in short-term cultures of CM cells generated from neoplastic lesions of 45 stage IIIC CM patients. Cells were analyzed at 6th in vitro passage. Patients were divided into 2 classes (LM and HM) based on the whole genome methylation profile of their tumor cells through the k-means algorithm. Kaplan-Meier function for OS was calculated for stage IIIC CM patients either unstratified (a), or stratified according to k-means-defined methylation classes (b). Dashed and solid lines refer to patients’ groups LM and HM, respectively. Vertical bars in the Kaplan-Meier curves represent censored patients. Cumulative survival by k-means-defined methylation group was evaluated using the Log-Rank test, reported P values were two sided.