Clinical characteristics of patients with colorectal cancer with double somatic mismatch repair mutations compared with Lynch syndrome

Patients with colorectal cancer (CRC) with mismatch repair-deficient (dMMR) tumours without MLH1 methylation or germline MMR pathogenic variants (PV) were previously thought to have Lynch syndrome (LS). It is now appreciated that they can have double somatic (DS) MMR PVs. We explored the clinical characteristics between patients with DS tumours and LS in two population-based cohorts.We included patients with CRC from Ohio 2013-2016 and Iceland...