STAT6 and metastatic melanoma: Phosphorylation of Erk, STAT1, STAT3 and STAT6 did not change significantly with ex vivo tremelimumab exposure in samples from five healthy donors and three patients with metastatic melanoma, while intracellular pp38, and pAKT decreased significantly from baseline with increasing concentrations of tremelimumab only in samples from patients with melanoma (Figure 3 and Figure S5).