MMTV‐PyMT mammary tumors' pieces were encapsulated and cultured in a multiwell plate and exposed to several drugs that targeted diverse molecular targets apart from DOX, including the Bcl‐2 inhibitor Navitoclax (ABT‐263), the actin polymerization inhibitor latrunculin A, and the MLC‐1 inhibitor S63845 or a vehicle control (Figure S10a, Supporting Information). This evidence concerns the gene MLC1 and breast cancer.