Sun et al. [38] demonstrated by transwell experiments that compared to those cultured in low glucose (5.56 mM), the breast cancer cells 7 cells (MCF-7) cultured in high glucose (25 mM) medium had stronger invasive ability, while the mRNA and protein expression of Glut1, MMP2 and MMP9 were significantly increased; besides, down-regulating Glut1 inhibited the invasion of MCF-7 cells and inhibited the expression of MMP2 and MMP9. Here, MMP9 is linked to breast cancer.