Podoplanin Expression in Canine Melanoma

A type I transmembrane protein, podoplanin (PDPN), is expressed in several normal cells such as lymphatic endothelial cells or pulmonary type I alveolar cells. We recently demonstrated that anticanine PDPN monoclonal antibody (mAb), PMab-38, recognizes canine PDPN of squamous cell carcinomas, but does not react with lymphatic endothelial cells. Herein, we investigated whether PMab-38 reacts with canine melanoma. PMab-38 reacted with 90% of melanoma cells (9/10 cases) using immunohistochemistry. Of interest, PMab-38 stained the lymphatic endothelial cells and cancer-associated fibroblasts in melanoma tissues, although it did not stain any lymphatic endothelial cells in normal tissues. PMab-38 could be useful for uncovering the function of PDPN in canine melanomas.