TGFB1 and melanoma: Correlative analysis of TGFβ1, TGFβ2 and sCTLA-4 levels in the three donor serum cohorts (Figure 3B) revealed a significant positive correlation between TGFβ2 and sCTLA-4 serum levels restricted solely to the melanoma serum cohort, and a weaker but significant correlation between TGFβ1 and sCTLA-4 in the healthy donor serum cohort.