TGFB3 and neoplasm: Interestingly, in contrast to this, expression of TGF-β3 and TGF-β3R in HCT116 cells in high density tumor microenvironment co-cultures was higher compared to that in control mono-culture (Fig. 6A: b,g), indicating the important role of the crosstalk in HCT116 and MRC-5 cells in co-cultures for tumor promotion.