Our results showed that paxillin Y31F overexpression inhibited the TGF-β1-induced migration (Figure 7A,C,D) and invasion (Figure 7B–D) of both MDA-MB-231 and MCF7 cells, suggesting that paxillin Tyr31 phosphorylation plays an important role in the migration and invasion of breast cancer cells. This evidence concerns the gene PXN and breast cancer.