ERBB2 and breast cancer: These live-cell time-lapse images come from a proof-of-concept study (Nguyen et al., 2018), which demonstrated the effects of an anticancer drug (the monoclonal antibodies trastuzumab, brand name Herceptin, used to treat HER2+ breast cancers) on a reconstituted tumor microenvironment, including cancer cells, immune cells, cancer-associated fibroblasts (CAFs), and endothelial cells (‘Materials and methods’).