PDPN and melanoma: The podoplanin mRNA was identified for the first time in the murine osteoblastic cell line MC3T3-E1 [1], and later it was found to be expressed in murine colon carcinoma and melanoma cells [2], in the stromal cells of peripheral lymphoid tissue [3], in skeletal muscle, heart, placenta, lung, skin, bone and brain [4,5].