SRPX2 and lip and oral cavity carcinoma: As receptors for SRPX2, urokinase plasminogen activator receptor (uPAR) [65] and hepatocyte growth factor (HGF) [61] are known, and it was found that SRPX2 was secreted into the culture supernatant by treating oral cancer cell lines with recombinant proteins of uPAR and HGF.