CDK4 and gallbladder cancer: Sch B can also trigger apoptosis of gallbladder cancer cells by modulating the expression of apoptosis-related proteins (up-regulating Bcl-2-associated X protein [Bax], cleaved caspase-9, cleaved caspase-3, cleaved PARP and down-regulating Bcl-2, NF-κB, cyclin D1 and cyclin-dependent kinase 4 [CDK-4]) (Xiang et al., 2014).