Humphris et al. [84] recently reported that MMR deficiency was found in 1% of their cohort of 385 resected pancreatic cancers samples, and all of these MMR-deficient tumours had different somatic inactivations of MutL homolog 1 (MLH1) and MutS protein homolog 2 (MSH2), without any germline mutations. The gene discussed is MSH2; the disease is mismatch repair cancer syndrome 1.