Carracedo et al. 37 observed that fibroblastic integrin α11 induction by increased matrix stiffness leading to myofibroblast differentiation required activin A. Similarly, breast cancer cells treated with TGF-β and cultured on polyacrylamide gels with increasing stiffness demonstrated increased EMT through PI3K/Akt signaling38, which suggests the involvement of activin A28. This evidence concerns the gene TGFB1 and breast cancer.