PRMT5 and triple-negative breast carcinoma: PRMT5 could catalyze the symmetric dimethylation of histones H2AR3, H3R2, H3R8, and H4R3 [16,38,39], so we added compounds A, B, and C and tadalafil at 50, 100, and 150 μM to MDA-MB-231 triple-negative breast cancer cells [40] and performed western blotting to detect the total protein levels of H4R3me2s and H3R8me2s 48 h later.