While 100% of 10-week old VN-/- mice showed low-grade dysplasia, 30% of 30-week old VN-/- mice developed high-grade dysplasia (Figure 3E) in addition to the low-grade dysplasia, suggesting that loss of epithelial cell-intrinsic Notch-1 promotes tumorigenesis. This evidence concerns the gene NOTCH1 and dysplasia.