Table 1

Selected biomarkers that have been evaluated in colorectal cancer

BiomarkerMolecular lesionFrequency in CRCPredictionPrognosisDiagnosis
KRASCodon 12/13 activating mutations; rarely codons 61, 117, 14640%YesPossible
BRAFV600E activating mutation10%ProbableProbableLynch syndrome
PIK3CAHelical and kinase domain mutations20%PossiblePossible
PTENLoss of protein by IHC30%Possible
Microsatellite instability (MSI)Defined as >30% unstable loci in the NCI consensus panel or >40% unstable loci in a panel of mononucleotide microsatellite repeats915%ProbableYesLynch Syndrome
Chromosome instability (CIN)Aneuploidy70%ProbableYes
18qLOHDeletion of the long arm of chromosome 1850%ProbableProbable
CpG island methylator phenotype (CIMP)Methylation of at least three loci from a selected panel of five markers15%+/−+/−
Vimentin (VIM)Methylation75%Early Detection
TGFBR2Inactivating mutations30%
TP53 mutationsInactivating mutations50%
APC mutationsInactivating mutations70%FAP
CTNNB1 (β-catenin)Activating mutations2%
Mismatch repair genesLoss of protein by IHC; methylation; inactivating mutations1–15%Lynch syndrome
  • CRC, colorectal cancer; FAP, familial adenomatous polyposis; IHC, immunohistochemistry.