TET2 (ten-eleven translocation 2), the gene encoding the methylcytosine dioxygenase 2, which catalyzes the conversion of the modified genomic base 5-methylcytosine (5mC) into 5-hydroxymethylcytosine (5hmC), is mutated in approximately 5-10% of human GCB-DLBCL. This evidence concerns the gene TET2 and diffuse large B-cell lymphoma.