We found that TGF-β expression was significantly increased in tumors derived from Treg co-cultured B16-BL6 cells compared with non co-cultured B16-BL6 cells (Figure 4A, p < 0.001), supporting the notion that Tregs are one of the main inducers of TGF-β expression in melanoma cells. The gene discussed is TGFB1; the disease is melanoma.