title: Epidermal growth factor (EGF) A61G polymorphism and EGF gene expression in normal colon tissue from patients with colorectal cancer.
abstract: BACKGROUND
  EGF/EGFR interactions are important mechanisms behind colorectal tumour development and growth. Recently a single nucleotide polymorphism in the EGF gene has been identified (EGF A61G). It may be a potential predictor for survival of patients receiving EGFR-inhibitor cetuximab treatment, but the clinical importance and the functional influence on EGF gene expression levels in colorectal cancer (CRC) patients have not yet been further assessed. The aim of the present study was to investigate the relationship between EGF A61G genotype and EGF gene expression levels in colorectal adenocarcinomas and normal colon tissue.
  
  
  METHODS
  Eighty-one CRC patients were included in the study. Tissue samples from normal colon, adenocacinomas and corresponding blood samples were analysed by real-time PCR for EGF gene expression and EGF A61G genotype, respectively.
  
  
  RESULTS
  Thirty-three percent were AA, 48% and 19% A/G and G/G respectively. We found a significantly lower median age in the A/A group compared to the G/G group, suggesting a later time of diagnosis in the G/G patients. There was a significant difference between the median EGF gene expression among the three genotypes in normal colon (p < 0.001) but not in adenocarcinomas. Furthermore, the median EGF gene expression was lower in CRC tissue than in normal colon samples, (0.13 (range 0.01-6.4) vs. 0.76, (range 0.013-5.55)).
  
  
  CONCLUSIONS
  We suggest that EGF A61G genotype has a functional influence on EGF gene expression in normal colon in CRC patients. The clinical implications warrant further investigations in prospective trials.
authors.affiliation: Department of Oncology, Vejle Hospital, Kabbeltoft 25, 7100 Vejle, Denmark. karen-lise.garm.spindler@vgs.regionsyddanmark.dk
authors.forename: Karen-Lise G
authors.initials: KL
authors.lastname: Spindler
authors.forename: Jens N
authors.initials: JN
authors.lastname: Nielsen
authors.forename: Dorthe
authors.initials: D
authors.lastname: Ornskov
authors.forename: Ivan
authors.initials: I
authors.lastname: Brandslund
authors.forename: Anders
authors.initials: A
authors.lastname: Jakobsen
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics* / Q000378:metabolism; D000368:Aged; D000369:Aged, 80 and over; D003106:Colon / Q000378:metabolism*; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000378:metabolism; D004815:Epidermal Growth Factor / Q000235:genetics* / Q000378:metabolism; D066246:ErbB Receptors / Q000235:genetics; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D005787:Gene Frequency; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide
chemical_list: D004815:Epidermal Growth Factor; D066246:ErbB Receptors