GPNMB and cancer: The precise effects are likely cell-dependent, but in an epithelial cell line, the expression of the GPNMB ITAM mutant (GPNMB YF) leads to a significant decrease in cell migration and sphere formation, which is consistent with the epithelial–mesenchymal transition (EMT), a process related to embryogenesis, wound healing, and cancer metastasis [113–115].