title: p53 status and prognosis of locally advanced prostatic adenocarcinoma: a study based on RTOG 8610.
abstract: BACKGROUND
  The p53 tumor suppressor gene (also known as TP53) is one of the most frequently mutated genes in human cancer. Several studies have shown that p53 mutations are infrequent in prostate cancer and are associated with advanced disease.
  
  
  OBJECTIVE
  We assessed the prognostic value of identifying abnormal p53 protein expression in the tumors of patients with locally advanced prostate cancer who were treated with either external-beam radiation therapy alone or total androgen blockade before and during the radiation therapy.
  
  
  METHODS
  The study population consisted of a subset of patients entered in Radiation Therapy Oncology Group protocol 8610 ("a phase III trial of Zoladex and flutamide used as cytoreductive agents in locally advanced carcinoma of the prostate treated with definitive radiotherapy"). Immunohistochemical detection of abnormal p53 protein in pretreatment specimens (i.e., needle biopsies or transurethral resections) was achieved by use of the monoclonal anti-p53 antibody DO7; specimens in which 20% or more of the tumor cell nuclei showed positive immunoreactivity were considered to have abnormal p53 protein expression. Associations between p53 protein expression status and the time to local progression, the incidence of distant metastases, progression-free survival, and overall survival were evaluated in univariate (logrank test) and multivariate (Cox proportional hazards model) analyses. Reported P values are two-sided.
  
  
  RESULTS
  One hundred twenty-nine (27%) of the 471 patients entered in the trial had sufficient tumor material for analysis. Abnormal p53 protein expression was detected in the tumors of 23 (18%) of these 129 patients. Statistically significant associations were found between the presence of abnormal p53 protein expression and increased incidence of distant metastases (P = .04), decreased progression-free survival (P = .03), and decreased overall survival (P = .02); no association was found between abnormal p53 protein expression and the time to local progression (P = .58). These results were independent of the Gleason score and clinical stage. A significant treatment interaction was detected with respect to the development of distant metastases: Among patients receiving both radiation therapy and hormone therapy, those with tumors exhibiting abnormal p53 protein expression experienced a reduced time to the development of distant metastases (P = .001); for patients treated with radiation therapy alone, the time to distant metastases was unrelated to p53 protein expression status (P = .91).
  
  
  CONCLUSIONS
  Determination of p53 protein expression status yield significant, independent prognostic information concerning the development of distant metastases, progression-free survival, and overall survival for patients with locally advanced prostate cancer who are treated primarily with radiation therapy.
  
  
  CONCLUSIONS
  The interaction of radiation therapy plus hormone therapy and abnormal p53 protein expression may provide a clinical link to experimental evidence that radiation therapy and/or hormone therapy act, at least in part, by the induction of apoptosis (a cell death program) and suggests that this mechanism may be blocked in patients whose tumors have p53 mutations.
authors.affiliation: Wayne State University, Harper Hospital, Detroit, MI 48201, USA.
authors.forename: D J
authors.initials: DJ
authors.lastname: Grignon
authors.forename: R
authors.initials: R
authors.lastname: Caplan
authors.forename: F H
authors.initials: FH
authors.lastname: Sarkar
authors.forename: C A
authors.initials: CA
authors.lastname: Lawton
authors.forename: E H
authors.initials: EH
authors.lastname: Hammond
authors.forename: M V
authors.initials: MV
authors.lastname: Pilepich
authors.forename: J D
authors.initials: JD
authors.lastname: Forman
authors.forename: J
authors.initials: J
authors.lastname: Mesic
authors.forename: K K
authors.initials: KK
authors.lastname: Fu
authors.forename: R A
authors.initials: RA
authors.lastname: Abrams
authors.forename: T F
authors.initials: TF
authors.lastname: Pajak
authors.forename: W U
authors.initials: WU
authors.lastname: Shipley
authors.forename: J D
authors.initials: JD
authors.lastname: Cox
mesh_terms: D000230:Adenocarcinoma / Q000737:chemistry* / Q000473:pathology / Q000556:secondary / Q000628:therapy; D000368:Aged; D000369:Aged, 80 and over; D018931:Antineoplastic Agents, Hormonal / Q000627:therapeutic use; D017024:Chemotherapy, Adjuvant; D017326:Clinical Trials, Phase III as Topic; D018450:Disease Progression; D018572:Disease-Free Survival; D005485:Flutamide / Q000627:therapeutic use; D015972:Gene Expression Regulation, Neoplastic; D016158:Genes, p53 / Q000235:genetics; D017273:Goserelin / Q000627:therapeutic use; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D011379:Prognosis; D011471:Prostatic Neoplasms / Q000737:chemistry* / Q000473:pathology / Q000628:therapy; D018714:Radiotherapy, Adjuvant; D016019:Survival Analysis; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*
chemical_list: D018931:Antineoplastic Agents, Hormonal; D016159:Tumor Suppressor Protein p53; D017273:Goserelin; D005485:Flutamide