According to a study on Cyclo(L-Leu-L-Pro) isolated from the sponge Callyspongia fistularis, the compound exhibited cytotoxic and apoptosis-inducing effects against human hepatocellular carcinoma HepG2 cells by significantly increasing the BAX/Bcl-2 protein expression ratio and activating caspase-3 [64]. Here, CASP3 is linked to hepatocellular carcinoma.