GPNMB/Osteoactivin [MD416R]

Glycoprotein non-metastatic gene B (GPNMB) is a type I transmembrane glycoprotein which shows homology to the pMEL17 precursor, a melanocyte-specific protein. GPNMB shows expression is seen in various tissues including skin, heart, kidney, lung, liver, and skeletal muscle, and overexpression in many types of cancers (e.g., melanoma, gliomas) and specific diseases like Lymphangioleiomyomatosis (LAM). It expresses in the lowly metastatic human melanoma cell lines and xenografts but not in the highly metastatic cell lines, indicating its involvement in growth delay and reduction of metastatic potential. GPNMB is typically localized to intracellular compartments in normal cells but primarily on the cell surface of tumor cells.