Thirty‐nine samples had a pathogenic B2M mutation and 77 had wild‐type B2M. With a median of 7.4 years of follow‐up, none of the 39 tumours with significant B2M mutations recurred compared to 14 of 77 (18.2%) of tumours with wild‐type B2M (P = 0.005). This evidence concerns the gene B2M and neoplasm.