A peer reviewed laboratory study found that bromelain, a proteolytic enzyme complex derived from pineapple, caused dramatic death of gastric cancer cells and chemotherapy resistant colon cancer cells in vitro, reducing viability by roughly 90 to 99 percent while activating multiple apoptosis pathways such as caspase activation, PARP cleavage, cytochrome c release, and suppression of survival signals including the Akt pathway and Bcl2 and MUC1 oncoproteins, findings that highlight bromelain’s mechanistic anti tumor potential but still require human clinical trials before any treatment claims can be made.