BCL2 and breast cancer: Consistently, Yan et al. (2012) observed that tanshinone IIA inhibited BT-20 human breast cancer cells’ ability to proliferate by activating ER stress (upregulating caspase-12, CHOP levels and downregulating Bcl-2 expression) and MAPK pathway (upregulating p-p38, p-JNK protein expression and downregulating p-ERK expression).