MAP2K4 and cancer: Intriguingly, comparing our methylation data with those of Mikkelsen et al.[16] we observed that the vast majority (96.4%) of genes harboring meK27 also contained meK4 and that only around 30% of the genes frequently hypermethylated in cancer presented the bivalent chromatin domain (meK4/meK27) in hESCs (Table S3).