Expression of drug resistance proteins in breast cancer, in relation to chemotherapy Academic Article uri icon

Overview

MeSH Major

  • Breast Neoplasms
  • Drug Resistance, Neoplasm
  • Gene Expression
  • Vault Ribonucleoprotein Particles

abstract

  • Drug resistance plays an important role in chemotherapy failure in breast cancer. We studied the expression of MDR1, MRP, LRP, DNA topoisomerases, p53 and Ki-67 in different groups of breast cancer patients in relation to chemotherapy. Tissues from 6 normal breasts and 20 primary operable, 40 locally advanced and 10 anthracycline-resistant metastatic breast cancers were assessed. Sequential samples of the same patient were available from 17 patients with locally advanced breast cancer undergoing neo-adjuvant chemotherapy and in 7 metastatic patients undergoing paclitaxel treatment. Protein expression was investigated by immunohistochemistry. Significantly higher protein expression was observed for Pgp, Ki-67 and p53 in the locally advanced breast cancers than in primary operable breast cancers. No other significant differences in protein expression were found among the 3 breast cancer groups. Expression of none of the markers that could be assessed (Pgp, MRP, LRP, p53 and Ki-67) in locally advanced breast cancer had predictive value for pathological response. Interestingly, after chemotherapy a significant decrease in percentage of Ki-67 positive tumor cells was observed, whereas the other markers did not vary substantially. Furthermore, considering all breast cancer samples, a cumulative dose of doxorubicin >400 mg/m2 inversely correlated with Ki-67 positivity. However, 2 patients with a pathological complete remission had only 5-10% Ki67-positive tumor cells before chemotherapy, indicating that Ki67 negativity itself is not responsible for chemoresistance. In conclusion, none of the known proteins related to multidrug resistance predicted response to chemotherapy in breast cancer, and resistant clones left behind generally had a low proliferation rate.

publication date

  • June 18, 1997

Research

keywords

  • Academic Article

Identity

Language

  • eng

Digital Object Identifier (DOI)

  • 10.1002/(SICI)1097-0215(19970529)71:5<787::AID-IJC16>3.0.CO;2-5

PubMed ID

  • 9180147

Additional Document Info

start page

  • 787

end page

  • 95

volume

  • 71

number

  • 5