title: Immunohistochemical detection of high-mobility group box 1 correlates with resistance of preoperative chemoradiotherapy for lower rectal cancer: a retrospective study.
abstract: BACKGROUND
  High-mobility group box 1 (HMGB1) is a nucleoprotein that is related to inflammation. It has been implicated in a variety of biologically important processes, including transcription, DNA repair, differentiation, development, and extracellular signaling. Recently, its important role in the process of tumor invasion, metastasis, and resistance to anti-cancer therapies has been demonstrated. In this study, we aimed to investigate the correlation of HMGB1 expression and resistance of rectal cancer patients to chemoradiotherapy (CRT) prior to curative operation.
  
  
  METHODS
  We retrospectively reviewed the data of 75 lower rectal cancer patients without complete pathological response who had received preoperative CRT and had undergone curative resection at the University of Tokyo Hospital between May 2003 and June 2010. HMGB1 expression in surgically resected specimens was evaluated using immunohistochemical detection and specimens were classified into high or low HMGB1 expression groups. Clinicopathologic features, degree of tumor reduction, regression of tumor grade, and patient survival were compared between the groups using non-paired Student's t-tests and Kaplan-Meier analysis.
  
  
  RESULTS
  A total of 52 (69.3%) patients had high HMGB1 expression, and 23 (30.7%) had low expression. HMGB1 expression was significantly correlated with histologic type (P=0.02), lymphatic invasion (P=0.02), and venous invasion (P=0.05). Compared to patients with low HMGB1 expression, those with high expression had a poorer response to CRT, in terms of tumor reduction ratio (42.2 versus 28.9%, respectively; P<0.01) and post-CRT histological tumor regression grade (56.5 versus 30.8% grade 2; respectively; P=0.03). However, no significant correlation was found between HMGB1 expression and recurrence-free and overall survival rates.
  
  
  CONCLUSIONS
  HMGB1 expression may be one of the key factors regulating the response of rectal cancer to preoperative CRT in terms of tumor invasiveness and resistance to therapy.
authors.affiliation: Department of Surgical Oncology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan. hongokumiko-tky@umin.ac.jp.
authors.forename: Kumiko
authors.initials: K
authors.lastname: Hongo
authors.affiliation: Department of Surgical Oncology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan. kaz-tky@umin.ac.jp.
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Kazama
authors.affiliation: Department of Transfusion Medicine, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan. tsuno-tky@umin.ac.jp.
authors.forename: Nelson H
authors.initials: NH
authors.lastname: Tsuno
authors.affiliation: Department of Surgical Oncology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan. ISHIHARA-1SU@h.u-tokyo.ac.jp.
authors.forename: Soichiro
authors.initials: S
authors.lastname: Ishihara
authors.affiliation: Department of Surgical Oncology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan. eijisunami@yahoo.co.jp.
authors.forename: Eiji
authors.initials: E
authors.lastname: Sunami
authors.affiliation: Department of Surgical Oncology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan. kitayama-1SU@h.u-tokyo.ac.jp.
authors.forename: Joji
authors.initials: J
authors.lastname: Kitayama
authors.affiliation: Department of Surgical Oncology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan. toshwatanabe@yahoo.co.jp.
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Watanabe
mesh_terms: D002288:Adenocarcinoma, Mucinous / Q000378:metabolism / Q000401:mortality / Q000556:secondary / Q000628:therapy; D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000378:metabolism*; D059248:Chemoradiotherapy / Q000401:mortality*; D019008:Drug Resistance, Neoplasm; D005260:Female; D005500:Follow-Up Studies; D024243:HMGB1 Protein / Q000378:metabolism*; D006801:Humans; D007124:Immunoenzyme Techniques; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009364:Neoplasm Recurrence, Local / Q000378:metabolism* / Q000401:mortality / Q000473:pathology / Q000628:therapy; D009367:Neoplasm Staging; D011300:Preoperative Care; D011379:Prognosis; D011836:Radiation Tolerance; D012004:Rectal Neoplasms / Q000378:metabolism* / Q000401:mortality / Q000473:pathology / Q000628:therapy; D012189:Retrospective Studies; D015996:Survival Rate
chemical_list: D014408:Biomarkers, Tumor; D024243:HMGB1 Protein; C585491:HMGB1 protein, human