To investigate the role of Bcl-2 family proteins in idelalisib-induced apoptosis, we treated HCC cells with idelalisib and found that it did not promote Bid, Bax and Noxa protein upregulation but did reduce the level of the anti-apoptotic proteins, such as Bcl-2 and Mcl-1 (Fig. 2a). This evidence concerns the gene MCL1 and hepatocellular carcinoma.