KMT2D was rarely mutated in CLL/SLL according to previous studies in Western countries (6–8), but 33 variants in 26 (6.9%) cases of CLL/SLL were found in this study (one case harbored 5 KMT2D variants and three cases harbored 2 KMT2D variants) (Figure 1C). Here, KMT2D is linked to B-cell chronic lymphocytic leukemia.