MDM4 and metastatic melanoma: We set very stringent criteria for retrieving functional SNPs based on the highest RegulomeDB rank (1a–1f), and eQTL were retrieved based on the most significant associations with skin and tissues prone to ‘hosting’ metastatic melanoma; therefore, it is likely that additional MDM2/MDM4 SNPs not yet identified are relevant for melanoma development and/or progression.