PDPN and cancer: PDPN plays crucial functions in lymphangiogenesis (Astarita, Acton & Turley, 2012; Renart et al., 2015), cancer invasiveness, extracellular matrix (ECM) remodeling (Hoshino et al., 2011; Ito et al., 2012) as well as promoting an immunosuppressive microenvironment (Sakai et al., 2018).