CASP9 and digestive system carcinoma: findings highlighting significant cytotoxic effects on MCF-7, NCI-H460, and SF-268 cells 8, later studies by Liu et al. in 2011 and 2014 showed that HMTA, derived from Ardisia brevicaulis, inhibits the proliferation of various human cancer cells, including PANC-1 (pancreatic), A549 (lung), SGC 7901 (gastrointestinal carcinoma), MCF-7 (breast), and PC-3 (prostate) cells, via caspase-3 and caspase-9 activation and the increase of the bax/bcl-2 protein expression ratio 11.