Abstract | 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.
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Authors | S Gregorcyk, Y Kang, D Brandt, P Kolm, G Singer, R R Perry |
Journal | Annals of surgical oncology
(Ann Surg Oncol)
Vol. 3
Issue 1
Pg. 8-14
(Jan 1996)
ISSN: 1068-9265 [Print] United States |
PMID | 8770296
(Publication Type: Comparative Study, Journal Article)
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Chemical References |
- ATP Binding Cassette Transporter, Subfamily B, Member 1
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Topics |
- ATP Binding Cassette Transporter, Subfamily B, Member 1
(metabolism)
- Aged
- Breast Neoplasms
(metabolism, pathology, therapy)
- Combined Modality Therapy
- Female
- Flow Cytometry
- Follow-Up Studies
- Humans
- Middle Aged
- Neoplasm Staging
- Prognosis
- Proportional Hazards Models
- Recurrence
- Retrospective Studies
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