To validate the target specificity of the PRMT5 inhibitors, we knocked out PRMT5 in three MCL cell lines (Maver-1, Granta-519, and Z-138) with different TP53 and ATM status (Fig. 1c and Supplementary Table S1) using CRISPR-Cas9 gene editing and evaluated the cytotoxic effect of the inhibitors. Here, ATM is linked to mantle cell lymphoma.