Surprisingly, when 9 × 105 unstimulated cancer cells were injected with 1 × 105 TGF-β-stimulated cancer cells, the number of GFP-positive colonies was larger than that with 1 × 106 unstimulated cancer cells alone (Fig. 3b, group “9:1” vs. “10:0”). This evidence concerns the gene TGFB1 and cancer.