Colorectal Cancer Biomarkers: Where Are We Now?

Table 1

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]
Clinical features	Associated with poor prognosis [54, 55]	Associated with proximal tumor location, lower staging, high grade differentiation, and abundance of tumor infiltrating lymphocytes [56, 57]	Correlates with proximal tumor location, higher prevalence in females, and BRAF mutations [58–61]