These data are corroborated by WES analysis of patient-derived primary and metastatic melanoma xenografts, which not only showed co-expression of RAD6B variants with wild-type RAD6B but also showed that these variants constitute the majority of the RAD6B transcriptome in contrast to RAD6A, which was predominantly represented by the wild-type form. This evidence concerns the gene UBE2B and metastatic melanoma.