Tumors formed by HT29-M6 human colon tumor cells without co-injection of fibroblasts, showed vascular vessel and Collagen I organization between those observed in tumor with co-injection of Snail1 KO or wt MEFs (Fig. 6c), suggesting that Snail1 KO MEFs prevents activation of resident fibroblasts. This evidence concerns the gene SNAI1 and neoplasm.