To analyze the OPN expression levels in cancer cell lines, we performed qPCR (Figure 1a) and Western blot (Figure 1b) analyses of the OPN expression in several cancer cell lines, including melanoma cell line MDA-MB435S; lung cancer cell lines A549, H460, and H358; and pancreatic cancer cell lines MIAPaca-2 and Panc-1. This evidence concerns the gene SPP1 and melanoma.