title: KRAS mutations are associated with specific morphologic features in colon cancer.
abstract: BACKGROUND
  Mutations in the KRAS gene occur at an early stage in the development of colorectal carcinoma. Importantly, KRAS mutation predicts resistance to anti-epidermal growth factor receptor therapy in stage IV disease.
  
  
  OBJECTIVE
  The aim of the current study is to correlate histologic features of colon cancer with the presence of KRAS mutations.
  
  
  METHODS
  Tumor tissue from 145 colon cancer resections was tested for KRAS mutations. KRAS mutation status was correlated with demographic and histologic characteristics. Statistical analysis was performed using the Pearson χ2 test and multivariate analysis.
  
  
  RESULTS
  KRAS mutations were present in 55/145 cases (37.9%), consistent with reported rates. KRAS mutations were significantly associated with usual adenocarcinoma morphology (multivariate P=0.014), peritumoral lymphocytic response (χ2, P=0.028; multivariate P=0.017), T3-T4 status (χ2, P=0.012; multivariate P=0.015), right-sided location (multivariate P=0.027), absence of lymphovascular invasion (multivariate P=0.008), and metastases at the time of resection (multivariate P=0.034). No association was found between KRAS mutation status and other factors.
  
  
  CONCLUSIONS
  Specific morphologic features in colon cancer suggest a higher likelihood of the presence of KRAS mutations. These morphologic features overlap partially with those associated with DNA mismatch repair gene mutations. If confirmed, these results may suggest a paradigm for directed KRAS testing.
authors.affiliation: Department of Pathology, Gulhane Military Medical Academy School of Medicine, Ankara, Turkey.
authors.forename: Armagan
authors.initials: A
authors.lastname: Gunal
authors.forename: Pei
authors.initials: P
authors.lastname: Hui
authors.forename: Selim
authors.initials: S
authors.lastname: Kilic
authors.forename: Ruliang
authors.initials: R
authors.lastname: Xu
authors.forename: Dhanpat
authors.initials: D
authors.lastname: Jain
authors.forename: Kisha
authors.initials: K
authors.lastname: Mitchell
authors.forename: Marie
authors.initials: M
authors.lastname: Robert
authors.forename: Barton
authors.initials: B
authors.lastname: Kenney
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics* / Q000473:pathology*; D000328:Adult; D003110:Colonic Neoplasms / Q000235:genetics / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D016283:Proto-Oncogene Proteins p21(ras); D012189:Retrospective Studies; D018631:ras Proteins / Q000235:genetics*
chemical_list: C117307:KRAS protein, human; D011518:Proto-Oncogene Proteins; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins