title: Preoperative Prediction of Lymph Node Status by Circulating Mir-18b and Mir-20a During Chemoradiotherapy in Patients with Rectal Cancer.
abstract: BACKGROUND
  In locally advanced rectal cancer, therapeutic success of preoperative chemoradiotherapy (CRT) ranges from resistance to complete regression. For those patients that respond well to CRT, local resection (LR) procedures are currently under investigation to minimize surgical morbidity and to improve functional outcome. To maintain the oncologic benefit appropriate staging procedures are essential. However, current clinical assessment and imaging techniques need further improvement.
  
  
  METHODS
  Five miRNAs associated with rectal cancer (miR-17, miR-18b, miR-20a, miR-31, and miR-193-3p) were analyzed in the plasma of rectal cancer patients (n = 42) using qPCR. Expression levels were assessed before, during and after CRT and analyzed in regard to patients' lymph node status obtained after total mesorectal excision and intensive histopathological work-up.
  
  
  RESULTS
  Four of the five miRNAs revealed reliable results in the plasma. miR-31 was excluded due to its low expression. MicroRNA-17, 18b, 20a, and 193-3p showed altering expression levels at different time points. Only 43% (miR-17), 43% (miR-18b), 53% (miR-20a), and 60% (miR-193-3p) showed a continuous in- or decrease of miRNA expression. The reduced expression of miR-18b and miR-20a during CRT was found to be significantly associated with postoperative lymph node negativity (p < 0.05).
  
  
  CONCLUSIONS
  MicroRNA expression in patient plasma changes during preoperative CRT. The alteration is not continuous and the meaning requires additional analysis on a larger patient cohort. The co-occurrence of reduced miR-18b and miR-20a expression with lymph node negativity after preoperative CRT could help to stratify the surgical procedure with respect to total mesorectal excision and LR if validated prospectively.
authors.affiliation: Department of General, Visceral and Pediatric Surgery, University Medical Center Göttingen, Göttingen, Germany, azadehazizian@yahoo.de.
authors.forename: Azadeh
authors.initials: A
authors.lastname: Azizian
authors.forename: Frank
authors.initials: F
authors.lastname: Kramer
authors.forename: Peter
authors.initials: P
authors.lastname: Jo
authors.forename: Hendrik A
authors.initials: HA
authors.lastname: Wolff
authors.forename: Tim
authors.initials: T
authors.lastname: Beißbarth
authors.forename: Robert
authors.initials: R
authors.lastname: Skarupke
authors.forename: Markus
authors.initials: M
authors.lastname: Bernhardt
authors.forename: Marian
authors.initials: M
authors.lastname: Grade
authors.forename: B Michael
authors.initials: BM
authors.lastname: Ghadimi
authors.forename: Jochen
authors.initials: J
authors.lastname: Gaedcke
mesh_terms: D000368:Aged; D014408:Biomarkers, Tumor / Q000097:blood*; D059248:Chemoradiotherapy / Q000379:methods; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D035683:MicroRNAs / Q000097:blood*; D008875:Middle Aged; D009367:Neoplasm Staging; D057234:Preoperative Period; D011379:Prognosis; D012004:Rectal Neoplasms / Q000473:pathology / Q000601:surgery / Q000628:therapy*
chemical_list: D014408:Biomarkers, Tumor; C581632:MIRN18 microRNA, human; C534451:MIRN20a microRNA, human; D035683:MicroRNAs