EZH1 and EZH2 methyltransferases, regulating H3K27me3, represent one of these targets suitable for developing novel therapeutic strategies for cancer therapy: they are involved both in normal and malignant hematopoiesis [3,50], and EZH2 dysregulation also occurs frequently in solid tumors such as melanoma, prostate, ovarian and lung cancers [5,51,52]. Here, EZH1 is linked to cancer.