CASP9 and neoplasm: Mechanistic analysis revealed that PCL family member PCL-2 promoted apoptosis by enhancing ROS production, upregulating the expression of pro-apoptotic genes (Bax, Caspase-3, and Caspase-9) at both mRNA and protein levels, and downregulating the expression of the anti-apoptotic gene Bcl-2, thereby suppressing tumor cell proliferation (Sun et al., 2022).