H2AX and neoplasm: The percentage of γ-H2AX-positive cells was significantly higher in ethanol-treated induced Aldh1b1−/− Msh2-LS non-tumour-bearing colonic mucosal epithelia (46%) compared with that in water-treated induced Aldh1b1−/− Msh2-LS colonic epithelia (0.5%) (P<0.0001, unpaired two-tailed Student's t-test) (Fig. 2G,H, Fig. 3G,H).