GPNMB and melanoma: Also, increased binding of SHP2 to C4S was associated with increased expression of transmembrane glycoprotein NMB (GPNMB) in hepatic cells [18] and of matrix-metalloproteinase (MMP)-9 in melanomas [12], due to sustained activation of phospho-38 MAPK (mitogen-activated protein kinase) and of phospho-ERK (Extracellular-signal regulated kinase)1/2).