To assess whether intestinal tumour formation is affected by acetaldehyde levels in Msh2-LS mice with either conditional or constitutive inactivation of Aldh1b1, mice were induced with tamoxifen (causing transient Cre activation in scattered LGR5-expressing intestinal epithelial stem cells) to conditionally inactivate Msh2. This evidence concerns the gene ALDH1B1 and intestinal neoplasm.