PDPN and melanoma: To investigate the role of PDPN in the pathogenesis of melanoma, protein expression of PDPN was analyzed by using 112 human melanoma tissue microarrays named HMelC112CD01 consisting of nontumor melanoma sample (n = 1), primary melanoma samples (n = 94), and melanoma distant metastasis samples (n = 17) (Fig. 1A).