PTGS2 and neoplasm: To determine the role of epithelial Notch-1 in controlling tumor-promoting factors, we analyzed the mRNA expression of various cell cycle, mitogenic, angiogenic, and tumor-promoting genes and identified a significant increased expression of the following genes in the colonic tissues of VN-/- mice compared to WT mice: cell division cycle 2 (Cdc2), c-Myc2, cyclin B1, cyclin E, Angiogenin-4, cyclooxygenase 2 (Cox2), hypoxia-inducible factor 1 alpha (Hif1a), matrix metalloproteinase 10 (Mmp10), Amphiregulin, Epiregulin, and Wnt5a (Figure 4A).