Although the negative regulation of TET2 gene expression concomitant with the increased abundance of 5hmC promoted by 5-aza-CdR in HeLa cells may seem controversial, a recent study of myeloid leukaemia treated with 5-aza-CdR described globally reduced levels of 5mC and increased levels of 5hmC, 5fC and 5caC, without altering TETs43. Here, TET2 is linked to myeloid leukemia.