Of the two IMPDH isoforms, only IMPDH2 has been found to be overexpressed in multiple cancer types.35 We found that IMPDH2 but not IMPDH1 protein and RNA expression positively correlated with the response to the IMPDH inhibitor AVN-944 in KMT2Ar-AML cases but, of note, not in the No-MLL group (Fig. 7a, b and Supplementary Fig. 7b). This evidence concerns the gene IMPDH1 and cancer.