title: Expression of the p73 protein in rectal cancers with or without preoperative radiotherapy.
abstract: OBJECTIVE
  To investigate p73 expression in normal mucosa, primary tumor, and metastasis in relation to radiotherapy (RT) response and clinicopathologic/biologic variables in rectal cancers.
  
  
  METHODS
  p73 was immunohistochemically examined on biopsies (unirradiated, n=102), distant (from the large bowel, n=82), and adjacent (adjacent to primary tumor, n=89) normal mucosa samples, primary tumors (n=131), and lymph node metastasis (n=32) from rectal cancer patients participating in a clinical trial of preoperative RT. Seventy-four patients received surgery alone and 57 received additional RT.
  
  
  RESULTS
  Cytoplasmic p73 was increased in the primary tumor compared with the distant or adjacent mucosa (p<or=0.0001). Nuclear (p=0.02) and cytoplasmic (p=0.003) p73 was higher in irradiated distant mucosa samples than in unirradiated ones, and nuclear p73 tended to be increased in irradiated primary tumors compared with unirradiated ones (p=0.06). p73 was positively related to cyclooxygenase-2 expression in irradiated tumors (p=0.03). p73-negative tumors tended to have a lower local recurrence after RT compared with unirradiated cases (p=0.06).
  
  
  CONCLUSIONS
  Normal epithelial cells seem more sensitive to RT than tumor cells regarding p73 expression. Patients with p73-negative rectal tumors may have a lower risk of local recurrence after RT.
authors.affiliation: Department of Oncology, Institute of Biomedicine and Surgery, Linköping University, Linköping, Sweden.
authors.forename: Daniella
authors.initials: D
authors.lastname: Pfeifer
authors.forename: Jingfang
authors.initials: J
authors.lastname: Gao
authors.forename: Gunnar
authors.initials: G
authors.lastname: Adell
authors.forename: Xiao-Feng
authors.initials: XF
authors.lastname: Sun
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016009:Chi-Square Distribution; D051546:Cyclooxygenase 2 / Q000032:analysis; D004268:DNA-Binding Proteins / Q000032:analysis*; D005260:Female; D016147:Genes, Tumor Suppressor; D006801:Humans; D007413:Intestinal Mucosa / Q000737:chemistry; D008207:Lymphatic Metastasis; D008297:Male; D008565:Membrane Proteins / Q000032:analysis; D008875:Middle Aged; D009687:Nuclear Proteins / Q000032:analysis*; D016016:Proportional Hazards Models; D012004:Rectal Neoplasms / Q000737:chemistry* / Q000473:pathology / Q000532:radiotherapy*; D000072160:Tumor Protein p73; D025521:Tumor Suppressor Proteins
chemical_list: D004268:DNA-Binding Proteins; D008565:Membrane Proteins; D009687:Nuclear Proteins; C000606460:TP73 protein, human; D000072160:Tumor Protein p73; D025521:Tumor Suppressor Proteins; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human