TNF-α exposure transforms both healthy breast epithelial cells and BC-derived cell lines, including ER+ (e.g., MCF7 and T47D) and TNBC (e.g., BT-549 and Hs578T), into cells with fibroblast-like morphology, reduced cell–cell adhesion, and cytoskeletal reorganization [64,88,89,90,91]. This evidence concerns the gene TNF and breast cancer.