PTGS1 and neoplasm: Angiogenesis and cell migration/invasion Individual genes involved in promoting angiogenesis (such as VEGFA and VEGFC) (Figure 4A), and cell invasion/migration (such as MMP1, MMP2, MMP7, MMP9, PLAU, PLAUR and the ITGB6 integrin) [35–37] were significantly down-regulated in the COX-1 knockdown cells (Figure 4A–4B), supportive of a role for COX-1 in promoting tumor metastasis.