Low expression of PHGDH loses its interaction with phosphofructokinase, which activates the hexosamine-sialic acid pathway, and increases sialylation of integrin αvβ3, thus facilitating cancer cell migration and invasion.265 Paweł et al. found that podoplanin (PDPN) from a subpopulation of breast cancer tumor-associated macrophages (TAMs) promotes cancer lymphangiogenesis and distant metastasis through attachment to lymphatic endothelial cells (LECs).266 And this process is predicated on the presence of a large amount of O-glycosylation in the extracellular structural domain of PDPN. Here, PDPN is linked to cancer.