Mutations of the B2M gene have been previously reported in 30% of MSI CRCs, with a higher proportion of B2M mutations in Lynch syndrome-associated compared with sporadic MSI CRCs.8 We therefore analysed the HEV densities separately in B2M-mutant (n = 21) and B2M-wild-type (n = 26) MSI CRCs. This evidence concerns the gene B2M and Lynch syndrome.