title: Clinical procedure for colon carcinoma tissue sampling directly affects the cancer marker-capacity of VEGF family members.
abstract: BACKGROUND
  mRNA levels of members of the Vascular Endothelial Growth Factor family (VEGF-A, -B, -C, -D, Placental Growth Factor/PlGF) have been investigated as tissue-based markers of colon cancer. These studies, which used specimens obtained by surgical resection or colonoscopic biopsy, yielded contradictory results. We studied the effect of the sampling method on the marker accuracy of VEGF family members.
  
  
  METHODS
  Comparative RT-qPCR analysis was performed on healthy colon and colon carcinoma samples obtained by biopsy (n = 38) or resection (n = 39) to measure mRNA expression levels of individual VEGF family members. mRNA levels of genes encoding the eicosanoid enzymes cyclooxygenase 2 (COX2) and 5-lipoxygenase (5-LOX) and of genes encoding the hypoxia markers glucose transporter 1 (GLUT-1) and carbonic anhydrase IX (CAIX) were included as markers for cellular stress and hypoxia.
  
  
  RESULTS
  Expression levels of COX2, 5-LOX, GLUT-1 and CAIX revealed the occurrence in healthy colon resection samples of hypoxic cellular stress and a concurrent increment of basal expression levels of VEGF family members. This increment abolished differential expression of VEGF-B and VEGF-C in matched carcinoma resection samples and created a surgery-induced underexpression of VEGF-D. VEGF-A and PlGF showed strong overexpression in carcinoma samples regardless of the sampling method.
  
  
  CONCLUSIONS
  Sampling-induced hypoxia in resection samples but not in biopsy samples affects the marker-reliability of VEGF family members. Therefore, biopsy samples provide a more accurate report on VEGF family mRNA levels. Furthermore, this limited expression analysis proposes VEGF-A and PlGF as reliable, sampling procedure insensitive mRNA-markers for molecular diagnosis of colon cancer.
authors.affiliation: Department of Biomedical Molecular Biology, Ghent University, Technologiepark 927, Zwijnaarde, 9052, Belgium.
authors.forename: Sarah
authors.initials: S
authors.lastname: Pringels
authors.forename: Nancy
authors.initials: N
authors.lastname: Van Damme
authors.forename: Bram
authors.initials: B
authors.lastname: De Craene
authors.forename: Piet
authors.initials: P
authors.lastname: Pattyn
authors.forename: Wim
authors.initials: W
authors.lastname: Ceelen
authors.forename: Marc
authors.initials: M
authors.lastname: Peeters
authors.forename: Johan
authors.initials: J
authors.lastname: Grooten
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019540:Area Under Curve; D014408:Biomarkers, Tumor / Q000032:analysis; D001706:Biopsy; D002277:Carcinoma / Q000378:metabolism* / Q000473:pathology / Q000601:surgery; D015687:Cell Hypoxia / Q000502:physiology; D003110:Colonic Neoplasms / Q000378:metabolism* / Q000473:pathology / Q000601:surgery; D013505:Digestive System Surgical Procedures / Q000009:adverse effects; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012333:RNA, Messenger / Q000032:analysis; D012372:ROC Curve; D060888:Real-Time Polymerase Chain Reaction; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013048:Specimen Handling / Q000379:methods*; D042461:Vascular Endothelial Growth Factor A / Q000032:analysis*
chemical_list: D014408:Biomarkers, Tumor; D012333:RNA, Messenger; D042461:Vascular Endothelial Growth Factor A