Our results demonstrated that TGF-β1 induced the expression of HMGA1 in both MCF-7 and MDA-MB-231 breast cancer cells, as shown by RT-qPCR and immunofluorescence staining; however, the TGF-β1-induced expression of HMGA was blocked by treatment of the cells with phosphatidylinositol-3 kinase (PI3K) signaling inhibitors. Here, TGFB1 is linked to breast cancer.