title: Prognostic relevance of stromal CD26 expression in rectal cancer after chemoradiotherapy.
abstract: BACKGROUND
  CD26 is a transmembrane glycoprotein whose role in various types of malignancies, along with the potential therapeutic and diagnostic targets, has been evaluated. Preoperative chemoradiotherapy (CRT) is an effective tool for local control of rectal cancer, but the rate of disease recurrence remains high. The aim of this study was to clarify the association between CD26 expression and rectal cancer after preoperative CRT.
  
  
  METHODS
  A total of 85 patients with rectal cancer who had undergone preoperative CRT were enrolled in this study. We investigated CD26 expression in residual tumors and the surrounding stromal tissue using immunohistochemistry. Additionally, stromal CD26 gene expression was assessed by real-time quantitative polymerase chain reaction.
  
  
  RESULTS
  Patients with high CD26 expression in cancer tissue more frequently had serosal invasion, vascular invasion, and a poor pathological response. High expression of CD26 in the tumor stroma was significantly correlated with histology and tumor recurrence. High CD26 expression in the stroma, but not the tumor itself, was significantly correlated with a poor prognosis. Patients expressing CD26 in the tumor stroma, based on transcriptional analysis, also had a significantly poorer prognosis than those without the expression. In multivariate analysis, lymph node metastasis and high stromal CD26 expression were identified as independent prognostic factors in patients with rectal cancer after neoadjuvant CRT.
  
  
  CONCLUSIONS
  Stromal CD26 expression after preoperative CRT was significantly associated with tumor recurrence and prognosis in rectal cancer patients. Our data suggest that stromal CD26 plays an important role and is a potential therapeutic target in tumor relapse.
authors.affiliation: Department of Gastrointestinal and Pediatric Surgery, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie, 514-8507, Japan. saigusa@clin.medic.mie-u.ac.jp.
authors.forename: Susumu
authors.initials: S
authors.lastname: Saigusa
authors.affiliation: Department of Gastrointestinal and Pediatric Surgery, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie, 514-8507, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Toiyama
authors.affiliation: Department of Gastrointestinal and Pediatric Surgery, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie, 514-8507, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Tanaka
authors.affiliation: Department of Gastrointestinal and Pediatric Surgery, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie, 514-8507, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Inoue
authors.affiliation: Department of Gastrointestinal and Pediatric Surgery, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie, 514-8507, Japan.
authors.forename: Koichiro
authors.initials: K
authors.lastname: Mori
authors.affiliation: Department of Gastrointestinal and Pediatric Surgery, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie, 514-8507, Japan.
authors.forename: Shozo
authors.initials: S
authors.lastname: Ide
authors.affiliation: Department of Gastrointestinal and Pediatric Surgery, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie, 514-8507, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Imaoka
authors.affiliation: Department of Gastrointestinal and Pediatric Surgery, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie, 514-8507, Japan.
authors.forename: Mikio
authors.initials: M
authors.lastname: Kawamura
authors.affiliation: Department of Gastrointestinal and Pediatric Surgery, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie, 514-8507, Japan.
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Mohri
authors.affiliation: Department of Gastrointestinal and Pediatric Surgery, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie, 514-8507, Japan.
authors.forename: Masato
authors.initials: M
authors.lastname: Kusunoki
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism*; D059248:Chemoradiotherapy; D018819:Dipeptidyl Peptidase 4 / Q000235:genetics / Q000378:metabolism*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009364:Neoplasm Recurrence, Local / Q000378:metabolism / Q000473:pathology* / Q000628:therapy; D009367:Neoplasm Staging; D018365:Neoplasm, Residual / Q000378:metabolism / Q000473:pathology* / Q000628:therapy; D011379:Prognosis; D012004:Rectal Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000628:therapy; D017154:Stromal Cells / Q000378:metabolism / Q000473:pathology; D015996:Survival Rate
chemical_list: D014408:Biomarkers, Tumor; C042807:DPP4 protein, human; D018819:Dipeptidyl Peptidase 4
keywords: CD26; Chemoradiotherapy; Prognosis; Rectal cancer; Tumor stroma