TET1 and B-cell chronic lymphocytic leukemia: The simultaneous acquisition model is supported by the observation that del(17p) involving the tumor suppressor TP53 is associated with global DNA demethylation in CLL B cells [10, 20] and by our observation that CLL patients from the cytogenetic intermediate- and/or high-risk groups present a reduction in 5-mCyt and 5-hmCyt levels and in DNMT3A and TET1/2 transcripts.