TGFB1 and breast cancer: In support of this notion, transwell migration and invasion assays demonstrated that treatment with TGF‐β1 enhanced the migratory and invasive ability of LM2‐4175 and Hs578T cells, but the noted effect of TGF‐β1 on breast cancer cell migration and invasion was compromised following knockdown of endogenous PSG9 in both cell lines (Figure 6C,D).