SPP1 and melanoma: Likewise, it was observed that pronounced (approximately 25-fold) upregulation of SPP1 encoding osteopontin, a secreted integrin-binding protein and established molecular prognostic marker for melanoma, occurred in response to GLO1 rescue expression, whereas SPP1 downregulation was not observed in GLO1_KO as compared to wildtype cells, again indicating a mechanistic discrepancy that might be related to the nature of CMV-driven forced rescue expression [40].