Immunohistochemical analysis of P-glycoprotein expression correlated with chemotherapy resistance in locally advanced breast cancer

Jungsil Ro, Aysegul Sahin, Jae Ro, Herbert Fritsche, Gabriel Hortobagyi, Mark Blick

Research output: Contribution to journalArticle

107 Scopus citations

Abstract

We analyzed the expression of P-glycoprotein in samples from 48 patients with locally advanced breast cancer. Tumor samples from 40 patients were obtained at mastectomy, which was performed after three cycles of induction chemotherapy consisting of doxorubicin, cyclophosphamide, vincristine, and prednisone. P-glycoprotein expression distributed focally was observed in 20 tumors by the immunoperoxidase method using the anti-p170-monoclonal antibody C219. The percentage of the tumor cell population expressing P-glycoprotein varied from <5% to >30%; expression was observed significantly more often in tumors that showed less than partial response to the preoperative chemotherapy. Furthermore, P-glycoprotein was not expressed in eight tumor specimens obtained at the time of diagnosis, prior to chemotherapy, from patients who subsequently had pathologic complete responses. A comparative study of P-glycoprotein expression before and after chemotherapy and upon recurrence of tumor was done on a limited number of samples. No significant differences in P-glycoprotein expression were found. Therefore, it is possible that an intrinsic, rather than acquired, drug resistance may play a role in the failure of induction chemotherapy for locally advanced breast cancer.

Original languageEnglish (US)
Pages (from-to)787-791
Number of pages5
JournalHuman Pathology
Volume21
Issue number8
DOIs
StatePublished - Jan 1 1990

Keywords

  • breast cancer
  • chemotherapy
  • immunohistochemistry
  • P-glycoprotein

ASJC Scopus subject areas

  • Pathology and Forensic Medicine

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