BCL2 and breast cancer: Ent-16β-17α-dihydroxykaurane (DHK) (C20H34O2, MW: 306.49, Figure 2) was isolated from the bark of Croton malambo, and exerted pro-apoptotic effects in human breast cancer cell line MCF-7 (IC50: 40.8 μM) after 72 h by downregulating BCL-2 expression at both the mRNA and protein levels, as well as decreasing human telomerase reverse transcriptase (hTERT) expression at the mRNA level [82].