Among twelve small-molecule compounds that may inhibit the growth of HCC cells screened using high-throughput screening technology, VE821 (Fig. 7A), a selective inhibitor of ataxia-telangiectasia-mutated and rad3-related protein (ATR), was found to reduce HCC cell proliferation, although its function in HCC has not been reported in detail. Here, ATR is linked to hepatocellular carcinoma.