Key characteristics of the three major CRC pathways.
Chromosomal instability (CIN)
Microsatellite instability (MSI)
CpG island methylation (CIMP)
Prevalence
80–85%
15–20%
Up to 20%
Molecular Events
Characterized by aneuploidy, inactivation of APC/b-catenin, clonal accumulation of genetic alterations in oncogenes and tumor suppressor genes, and allelic losses and gains [49–51]
Mutations/epimutations in the MMR genes result in extensive insertions and/or deletions in microsatellites
Hypermethylation of multiple promoter CpG island loci, such as hMLH1 [9, 52]. BRAF mutations [53]