However, while we did not see a sensitizing effect of the BCL-2 inhibitor venetoclax to lapatinib in the HER2-amplified breast cancer cell lines BT-474 or MDA-MB-453, we did see added toxicity with the tool BCL-xL inhibitor A-1331852, which was similar to that afforded by A-1210477 (Suplementary Fig. 4A, C). Here, BCL2 is linked to breast cancer.