title: The utility of diagnostic biopsy specimens for predictive molecular testing in colorectal cancer.
abstract: OBJECTIVE
  If stratified medicine is to be applied in the neoadjuvant setting, predictive testing will have to be undertaken on preoperative diagnostic biopsy specimens. The aim of this study was to evaluate whether a diagnostic biopsy was adequately representative of the main tumour in colorectal cancer.
  
  
  RESULTS
  Thirty cases of paired biopsy and subsequent resection specimens were randomly selected. Samples were screened for mutation in KRAS (codons 12/13, 61, and 146), BRAF (codon 600 and exon 11), PIK3CA (exons 1, 9, and 20), TP53 (exons 5-8), and microsatellite instability, using the quick multiplex consensus or standard polymerase chain reaction (PCR) protocols followed by high-resolution melting analysis. A total of 570 paired PCR tests were performed for mutation detection, and identical results were obtained in both biopsy and resection specimens in 569 tests (>99% concordance). Four cases (13%) showed microsatellite instability, and, in all four cases, instability was seen at identical mononucleotide markers in both biopsy and matched resection specimens.
  
  
  CONCLUSIONS
  This is the first study to show that diagnostic biopsy specimens, even though they are a tiny sample of the tumour, are sufficiently representative for use in predictive testing for early driver mutations in colorectal cancer.
authors.affiliation: Division of Pathology, School of Molecular Medical Sciences, University of Nottingham, Nottingham, UK.
authors.forename: Wakkas
authors.initials: W
authors.lastname: Fadhil
authors.forename: Salih
authors.initials: S
authors.lastname: Ibrahem
authors.forename: Rashmi
authors.initials: R
authors.lastname: Seth
authors.forename: Ghada
authors.initials: G
authors.lastname: AbuAli
authors.forename: Krishna
authors.initials: K
authors.lastname: Ragunath
authors.forename: Philip
authors.initials: P
authors.lastname: Kaye
authors.forename: Mohammad
authors.initials: M
authors.lastname: Ilyas
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology*; D001706:Biopsy / Q000379:methods*; D058534:Class I Phosphatidylinositol 3-Kinases; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology*; D055088:Early Detection of Cancer; D005820:Genetic Testing; D006801:Humans; D053842:Microsatellite Instability; D025202:Molecular Diagnostic Techniques / Q000379:methods*; D009154:Mutation / Q000235:genetics; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics / Q000378:metabolism; D011237:Predictive Value of Tests; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics / Q000378:metabolism; D016283:Proto-Oncogene Proteins p21(ras); D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism; D018631:ras Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D058534:Class I Phosphatidylinositol 3-Kinases; D019869:Phosphatidylinositol 3-Kinases; D011518:Proto-Oncogene Proteins; D048493:Proto-Oncogene Proteins B-raf; D016283:Proto-Oncogene Proteins p21(ras); D016159:Tumor Suppressor Protein p53; D018631:ras Proteins; C117307:KRAS protein, human; C484760:PIK3CA protein, human; C482119:BRAF protein, human