Table 1 Comparison of microsatellite-unstable colorectal cancers
From: Molecular genetics of microsatellite-unstable colorectal cancer for pathologists
|  | (A) Sporadic dMMR – MLH1 Promoter Hypermethylation | (B) Lynch Syndrome | (C) Sporadic dMMR – Somatic MMR Mutations | (D) Constitutional Mismatch Repair Deficiency (CMMRD) |
|---|---|---|---|---|
Germline mutation | None | One allele of a MMR gene (MLH1, PMS2, MSH2, MSH6) | None | Both alleles of a MMR gene (MLH1, PMS2, MSH2, MSH6) |
Somatic mutation | BRAF V600E | 2nd allele of the mutated MMR gene | Both alleles of a MMR gene (MLH1, PMS2, MSH2, MSH6) | None |
Epigenetic alteration | Somatic biallelic promoter methylation of MLH1 | Germline deletion in 3′ end of EPCAM leads to MSH2 methylation | None | None |
Intense Lifelong Screening | No | Yes | No | Yes |