PRMT5 binding to HSP90 and methylated arginine in HSP90 were reduced in HTLV-1-infected and ATL cell lines upon treatment with PRMT5 inhibitor (Figure 3D), indicating that PRMT5 inhibitors show the inhibition of cell proliferation via the suppression of HSP90 activity in NDRG2low ATL, but not in T-ALL. Here, HSP90AA1 is linked to acute lymphoblastic leukemia.