title: Studies on p53, BAX and Bcl-2 protein expression and microsatellite instability in stage III (UICC) colon cancer treated by adjuvant chemotherapy: major prognostic impact of proapoptotic BAX.
abstract: We evaluated the expression patterns of proapoptotic BAX, antiapoptotic Bcl-2 and p53, the proposed upstream effector of these molecules, as potential prognostic markers in UICC stage III colon cancer by immunohistochemical staining. To identify high-frequency microsatellite instability (MSI+) individuals, we performed single-strand conformation polymorphism-based analysis for BAT26. A total of 188 patients who had received 5-fluorouracil (5-FU)-based adjuvant chemotherapy (5-FU/folinic acid or 5-FU/levamisole) were enrolled. Median follow-up was 84.5 months. We found that BAX, Bcl-2 and p53 protein expressions were high or positive in 59, 70 and 50% of 188 cases, respectively. MSI+ tumours were detected in 9% of 174 evaluable patients. BAX or Bcl-2 was correlated with a higher degree of differentiation or left-sided tumours (P=0.01 or P=0.03, respectively); MSI was correlated with right-sided tumours (P<0.0001). In contrast to p53, Bcl-2, or MSI, low BAX, advanced pN category, low grade of differentiation and treatment with 5-FU/levamisole were univariately associated with poorer disease-free survival (DFS) (P=0.0005, P=0.001, P=0.005 and P=0.01, respectively) and poorer overall survival (OS) (P=0.002, P=0.0001, P=0.003 and P=0.02, respectively). Besides pN category and treatment arm, BAX was an independent variable related to both OS and DFS (P=0.003 and P=0.001, respectively). In both univariate and multivariate analysis, the p53-/BAX high in comparison with the p53+/BAX high subset conferred a significantly improved DFS (P=0.03 and P=0.03, respectively) as well as a marginally improved OS (P=0.07 and P=0.08, respectively). BAX protein expression may be of central significance for clinical outcome to 5-FU-based adjuvant chemotherapy in stage III colon cancer, and bivariate analysis of p53/BAX possibly may provide further prognostic evidence.
authors.affiliation: Department of Internal Medicine I, University Hospital, Tübingen, Germany. oliver.nehls@med.uni-tuebingen.de
authors.forename: O
authors.initials: O
authors.lastname: Nehls
authors.forename: T
authors.initials: T
authors.lastname: Okech
authors.forename: C-J
authors.initials: CJ
authors.lastname: Hsieh
authors.forename: T
authors.initials: T
authors.lastname: Enzinger
authors.forename: M
authors.initials: M
authors.lastname: Sarbia
authors.forename: F
authors.initials: F
authors.lastname: Borchard
authors.forename: H-H
authors.initials: HH
authors.lastname: Gruenagel
authors.forename: V
authors.initials: V
authors.lastname: Gaco
authors.forename: H G
authors.initials: HG
authors.lastname: Hass
authors.forename: H T
authors.initials: HT
authors.lastname: Arkenau
authors.forename: J T
authors.initials: JT
authors.lastname: Hartmann
authors.forename: R
authors.initials: R
authors.lastname: Porschen
authors.forename: M
authors.initials: M
authors.lastname: Gregor
authors.forename: B
authors.initials: B
authors.lastname: Klump
mesh_terms: D000368:Aged; D017209:Apoptosis; D017024:Chemotherapy, Adjuvant; D003110:Colonic Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology*; D005260:Female; D005472:Fluorouracil / Q000627:therapeutic use*; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D053842:Microsatellite Instability; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics*; D016159:Tumor Suppressor Protein p53 / Q000235:genetics*; D051028:bcl-2-Associated X Protein / Q000235:genetics*
chemical_list: D019253:Proto-Oncogene Proteins c-bcl-2; D016159:Tumor Suppressor Protein p53; D051028:bcl-2-Associated X Protein; D005472:Fluorouracil