JAK1 and leukemia: Only 12 genes with 27 presumably pathogenic gene variants were among the most frequently mutated ones in this type of leukaemia [1, 20, 23, 24]: ARID1A, CTCF, DNM2, FAT1, FBXW7, H3F3A, JAK1, JAK3, KMT2D, NOTCH1, PHF6, and WT1. Interestingly, the affectation of 4 of these genes (DNM2, JAK1, JAK3 and CTCF) has been described in Early T-cell Precursor Acute lymphoblastic leukaemia (ETP T-ALL) [1, 25–27].