MAX and hepatocellular carcinoma: A novel organic selenium compound, phenyl‐2‐pyrimidinyl ketone 4‐allyl‐3‐amino selenourea (CU27), is developed, which can bind c‐Myc bHLH/LZ domains, block c‐Myc‐Max complex formation, and prevent its occupancy on target gene promoters in hepatocellular carcinoma (HCC) cells.