title: Overexpression of P70 S6 kinase protein is associated with increased risk of locoregional recurrence in node-negative premenopausal early breast cancer patients.
abstract: The RPS6KB1 gene is amplified and overexpressed in approximately 10% of breast carcinomas and has been found associated with poor prognosis. We studied the prognostic significance of P70 S6 kinase protein (PS6K) overexpression in a series of 452 node-negative premenopausal early-stage breast cancer patients (median follow-up: 10.8 years). Immunohistochemistry was used to assess PS6K expression in the primary tumour, which had previously been analysed for a panel of established prognostic factors in breast cancer. In a univariate analysis, PS6K overexpression was associated with worse distant disease-free survival as well as impaired locoregional control (HR 1.80, P 0.025 and HR 2.50, P 0.006, respectively). In a multivariate analysis including other prognostic factors, PS6K overexpression remained an independent predictor for poor locoregional control (RR 2.67, P 0.003). To our knowledge, P70 S6 kinase protein is the first oncogenic marker that has prognostic impact on locoregional control and therefore may have clinical implications in determining the local treatment strategy in early-stage breast cancer patients.
authors.affiliation: Department of Surgery, Leiden University Medical Center, Albinusdreef 2, 2300 RC Leiden, The Netherlands.
authors.forename: J A
authors.initials: JA
authors.lastname: van der Hage
authors.forename: L J C M
authors.initials: LJ
authors.lastname: van den Broek
authors.forename: C
authors.initials: C
authors.lastname: Legrand
authors.forename: P C
authors.initials: PC
authors.lastname: Clahsen
authors.forename: C J A
authors.initials: CJ
authors.lastname: Bosch
authors.forename: E C
authors.initials: EC
authors.lastname: Robanus-Maandag
authors.forename: C J H
authors.initials: CJ
authors.lastname: van de Velde
authors.forename: M J
authors.initials: MJ
authors.lastname: van de Vijver
mesh_terms: D000328:Adult; D001943:Breast Neoplasms / Q000235:genetics* / Q000473:pathology*; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D020869:Gene Expression Profiling; D006801:Humans; D007150:Immunohistochemistry; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D009367:Neoplasm Staging; D017697:Premenopause; D011379:Prognosis; D038762:Ribosomal Protein S6 Kinases, 70-kDa / Q000096:biosynthesis* / Q000235:genetics*; D012307:Risk Factors
chemical_list: D038762:Ribosomal Protein S6 Kinases, 70-kDa