MSH2 and neoplasm: Ethanol-treated conditional Aldh1b1flox/flox Msh2-LS mice showed colonic epithelial hyperproliferation and colonic tumours in 42% of animals that were treated with ethanol in an average of 4.5 months, statistically significantly greater than 0% of control water-treated conditional Aldh1b1flox/flox Msh2-LS mice showing colonic hyperproliferation/tumour formation.