p-Glycoprotein expression as a predictor of breast cancer recurrence

Ann Surg Oncol. 1996 Jan;3(1):8-14. doi: 10.1007/BF02409045.


Background: Many new prognostic factors for breast cancer have been described, and yet the ability to predict patient outcomes remains poor. Overexpression of p-glycoprotein (p-gp), the multidrug resistance efflux pump, confers a worse prognosis to patients with certain leukemias and other tumors. The purpose of this study was to analyze the potential usefulness of p-gp expression as a prognostic factor in patients with breast cancer.

Methods: Paraffin blocks were obtained from 55 previously untreated patients who underwent surgery between 1987 and 1988. To determine p-gp expression, tumor cell suspensions were incubated with the p-gp-specific C219 monoclonal antibody and analyzed using an indirect immunofluorescent flow cytometric assay.

Results: Twenty-four (44%) of the tumors were p-gp positive and 31 (56%) were p-gp negative. Among the p-gp positive patients, 65% had recurrence of their disease, whereas only 13% of the p-gp negative patients experienced recurrence (p = 0.0001). The 5-year disease-free rate for p-gp positive patients was 39% compared with 83% for p-gp negative patients (p = 0.0001). In univariate analysis examining 10 different variables, significant predictors of recurrence were p-gp, stage, and tumor size. Multivariate analysis using Cox Proportional Hazards regression showed that only p-gp and stage were significant independent predictors of recurrence (p = 0.0002).

Conclusions: p-gp is frequently expressed in patients with untreated breast cancer, with p-gp-positive patients being at significantly greater risk for disease recurrence. p-gp appears to be a useful prognostic factor in breast cancer and could potentially help guide management.

Publication types

  • Comparative Study

MeSH terms

  • ATP Binding Cassette Transporter, Subfamily B, Member 1 / metabolism*
  • Aged
  • Breast Neoplasms / metabolism*
  • Breast Neoplasms / pathology
  • Breast Neoplasms / therapy
  • Combined Modality Therapy
  • Female
  • Flow Cytometry
  • Follow-Up Studies
  • Humans
  • Middle Aged
  • Neoplasm Staging
  • Prognosis
  • Proportional Hazards Models
  • Recurrence
  • Retrospective Studies


  • ATP Binding Cassette Transporter, Subfamily B, Member 1