title: Molecular diagnostics of colorectal cancer.
abstract: BACKGROUND
  Of all gastrointestinal tract epithelial malignancies, molecular diagnostics has impacted colorectal cancer the most. Molecular testing can detect sporadic and inherited colorectal cancers that arise through the microsatellite instability pathway and can determine the efficacy of targeted drug therapy.
  
  
  OBJECTIVE
  To review the microsatellite instability pathway of colorectal carcinoma carcinogenesis and to demonstrate the diagnostic utility of molecular testing in the detection of patients with Lynch syndrome, an inherited disorder of this pathway. Also, to review the significance of detection of KRAS and BRAF gene mutations in predicting the response to anti-epidermal growth factor receptor therapies.
  
  
  METHODS
  This article is based on original publications and review articles that are accessible through the PubMed biomedical database (US National Library of Medicine).
  
  
  CONCLUSIONS
  In modern pathology practice, molecular testing is a standard tool that is used to diagnose an inherited colorectal cancer predisposition syndrome (Lynch syndrome) and to help predict outcome and response to therapy for patients with advanced colorectal cancer.
authors.affiliation: Gastrointestinal Pathology, Caris Research Institute, Caris Life Sciences, Phoenix, Arizona, USA.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Bedeir
authors.forename: Alyssa M
authors.initials: AM
authors.lastname: Krasinskas
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis* / Q000235:genetics / Q000378:metabolism; D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000235:genetics / Q000378:metabolism; D003123:Colorectal Neoplasms, Hereditary Nonpolyposis / Q000175:diagnosis / Q000235:genetics; D053843:DNA Mismatch Repair; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D053842:Microsatellite Instability; D025202:Molecular Diagnostic Techniques / Q000379:methods*; D017354:Point Mutation; D011518:Proto-Oncogene Proteins / Q000235:genetics; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics; D016283:Proto-Oncogene Proteins p21(ras); D039781:PubMed; D018631:ras Proteins / Q000235:genetics
chemical_list: D014408:Biomarkers, Tumor; C117307:KRAS protein, human; D011518:Proto-Oncogene Proteins; C482119:BRAF protein, human; D048493:Proto-Oncogene Proteins B-raf; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins