title: Cyclooxygenase-2 expression in pretreatment biopsy as a predictor of tumor responses after preoperative chemoradiation in rectal cancer.
abstract: OBJECTIVE
  To determine whether cyclooxygenase-2 (COX-2) expression in pretreatment biopsy specimens is a useful predictive marker of tumor response to preoperative chemoradiation (CRT) in rectal cancer.
  
  
  METHODS
  Case series.
  
  
  METHODS
  Colorectal cancer clinic.
  
  
  METHODS
  Thirty patients with locally advanced rectal cancer were given preoperative CRT of 5040 cGy for 6 weeks with concurrent administration of 5-fluorouracil and leucovorin.
  
  
  METHODS
  Immunohistochemical staining for COX-2 and angiogenesis markers (vascular endothelial growth factor, thymidine phosphorylase, and CD34) were performed on biopsy specimens obtained before preoperative CRT. The responses to preoperative CRT were assessed by radiologic downsizing (measured using magnetic resonance imaging volumetry), histopathologic downstaging, and a 3-point tumor regression grade (TRG) evaluation, based on the ratio of residual cancer to fibrosis.
  
  
  RESULTS
  Tumor downstaging was seen in 15 patients (50.0%) and nodal downstaging was noted in 14 patients (46.7%). Tumor regression grade 1 (good response) was shown by 7 patients (23.3%); TRG2 (moderate response) in 15 patients (50.0%); and TRG3 (poor response) in 8 patients (26.7%). Patients with COX-2 overexpression were more likely to show a poor TRG (P = .003) and were less likely to achieve histopathologic nodal downstaging (P = .03) than those with normal COX-2 expression. Vascular endothelial growth factor overexpression was found to be associated with COX-2 overexpression (P = .02).
  
  
  CONCLUSIONS
  Overexpression of COX-2 in pretreatment biopsies might be predictive of poor tumor regression after preoperative CRT. Administration of COX-2 inhibitors to patients with COX-2 overexpression, in an attempt to improve response rate to preoperative CRT, warrants assessment in clinical trials.
authors.affiliation: Department of Surgery, Yonsei University College of Medicine, Seodamun-Gu Shincheon Dong 134, Seoul, Korea.
authors.forename: Byung Soh
authors.initials: BS
authors.lastname: Min
authors.forename: Yoon Jung
authors.initials: YJ
authors.lastname: Choi
authors.forename: Hong Ryull
authors.initials: HR
authors.lastname: Pyo
authors.forename: Hogeun
authors.initials: H
authors.lastname: Kim
authors.forename: Jinsil
authors.initials: J
authors.lastname: Seong
authors.forename: Hyun Cheol
authors.initials: HC
authors.lastname: Chung
authors.forename: Sun Young
authors.initials: SY
authors.lastname: Rha
authors.forename: Nam Kyu
authors.initials: NK
authors.lastname: Kim
mesh_terms: D000328:Adult; D000368:Aged; D042501:Angiogenic Proteins / Q000378:metabolism; D000970:Antineoplastic Agents / Q000008:administration & dosage; D015331:Cohort Studies; D051546:Cyclooxygenase 2 / Q000378:metabolism*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D018714:Radiotherapy, Adjuvant; D012004:Rectal Neoplasms / Q000378:metabolism* / Q000473:pathology / Q000628:therapy*; D012074:Remission Induction; D016896:Treatment Outcome; D047368:Tumor Burden
chemical_list: D042501:Angiogenic Proteins; D000970:Antineoplastic Agents; D051546:Cyclooxygenase 2