AOM/DSS treatment ↓ serum vitamin D levels; vitamin D administration significantly ↓ the number and colorectal neoplasms in a dose-dependent manner by up to 59%, ameliorated colon length shortening, ↓ cell proliferation in the colon↓ β-catenin expression in vivo, ↑β-catenin binding to E-cadherin in vivo. The gene discussed is CDH1; the disease is colorectal neoplasm.