APC and Leigh syndrome: This is illustrated by experiments in which antibiotic treatment reduced tumor development in Apc+/-;Msh2−/− mice but not in Apc+/-;Msh2+/- mice, suggesting a specific sensitivity of Msh2-deficient cells to microbe-mediated oncogenic effects.7 In addition, a recent study has prospectively characterized the composition of gut microbiota at taxonomic and functional levels in human LS patients and found increased relative abundance of Desulfovibrio to be associated with adenoma development.8 However, a cause/consequence relationship could not be established.