KMT2D and Burkitt lymphoma: These mutation patterns share some features (MYC, DDX3X) but not all (KMT2D, BCL2) with BL.28,29 In a similar vein, MHG did not have a high rate of mutation of TCF3 or its negative regulator ID3 typical of BL.28-30 Expression of ID3 was reduced in MHG compared with BL, whereas TCF3 was expressed at similar levels (Data Supplement), which suggests that alternative regulatory mechanisms operate for these genes in MHG.