20 In combination with the current study, 91 dMMR tumours with B2M deficiency did not recur, seven of which were stage III tumours, compared with 43 of 234 (18.4%) with proficient B2M that did recur. A log‐rank test for the difference in numbers of recurrence in B2M mutation/B2M loss and B2M‐proficient, stratified by study, yields a χ2 of 19.01, P = 0.00001. This evidence concerns the gene B2M and neoplasm.