We here analysed the prognostic significance of MSI and mutations of the Beta2-Microglobulin (B2M) gene, which occur in about 30% of MSI-H colon cancer, in the cohort of the prospective FOGT-4 (Forschungsruppe Onkologie Gastrointestinale Tumoren, FOGT) trial. Here, B2M is linked to colonic neoplasm.