SPP1 and metastatic melanoma: Some of the striking changes in metastatic melanoma were identified in genes encoding proteins involved in the regulating and remodeling of the extracellular matrix (ECM), such as osteopontin (OPN), collagen triple helix containing protein 1 (CTHRC1) [10, 11], and serpin peptidase inhibitor, clade A (alpha-1 antiproteinase, antitrypsin), member 3 (SERPINA3) [12, 13].