To gain further insight into genes that may drive CLL and PTCL we considered the simplest explanation for the tumor suppressor function of Dnmt3a in the prevention of mouse CLL and PTCL - loss of methylase activity of Dnmt3a results in hypomethylation and overexpression of subset of genes whose inappropriate expression contributes to cellular transformation. Here, DNMT3A is linked to B-cell chronic lymphocytic leukemia.