PDPN and cancer: Parental TPC1 and BcPAP cells differ in the expression of MMP-2 and MMP-9, with BcPAP displaying very low expression of both MMPs analyzed, hence the differences in MMP-2 and MMP-9 expression following PDPN silencing in the two cell lines suggest that they may play a role in cancer progression, with different MMPs being involved, depending on the type of cells.