DNMT3A is thought to be critical in the control of DNA methylation in CLL, and such an assertion is supported by the observation that DNMT3A knockdown in rodent hematopoietic stem cells results in CLL development [24] and that DNMT3A is present in the top 1% of the under-expressed genes in human CLL B cells [25]. This evidence concerns the gene DNMT3A and B-cell chronic lymphocytic leukemia.