Analysis of CREB protein expression by Western Blot demonstrates that while levels of total CREB protein remain similar in all melanoma cell lines, the levels of its phosphorylation at Serine 133 (pCREB), a critical functional phosphorylation site, were significantly higher (approximately 5-fold increase) in metastatic melanoma cell lines (A375SM and C8161-c9) as compared to non-metastatic melanoma cell lines (SB2 and DX3) (Figure 2A). Here, CREB1 is linked to melanoma.