title: Multidrug resistance associated genes MRP1, MRP2 and MRP3 in primary and anthracycline exposed breast cancer.
abstract: BACKGROUND
  Multidrug resistance associated proteins MRP1, MRP2 and MRP3 confer in vitro multidrug resistance. We investigated their role in breast cancer resistance to anthracycline-based chemotherapy.
  
  
  METHODS
  Using real-time reverse transcriptase polymerase chain reaction (RT-PCR) and immunohistochemistry (IHC), the expression of MRP1 - 3 was quantified in nine breast cancer cell lines and 30 breast carcinoma samples.
  
  
  RESULTS
  MRP1 - 3 mRNA was detectable in all breast cancer cell lines and tumor samples. No increase of expression was detected between untreated carcinoma and post-neoadjuvant anthracycline treatment tumor samples. IHC failed to detect the proteins. MRP1 - 3 expression was not associated with tumor response to treatment or with outcome.
  
  
  CONCLUSIONS
  MRP1 - 3 are expressed in breast cancer cells, but are not detected with IHC. We have found no evidence linking these proteins to clinical drug resistance in a small but well-documented series of breast cancer samples.
authors.affiliation: Department of Experimental Therapy, Cancer Institute / Antoni van Leeuwenhoek Hospital, Amsterdam, The Netherlands. m.vd.vijver@nki.nl
authors.forename: Ian F
authors.initials: IF
authors.lastname: Faneyte
authors.forename: Petra M P
authors.initials: PM
authors.lastname: Kristel
authors.forename: Marc J
authors.initials: MJ
authors.lastname: van de Vijver
mesh_terms: D018943:Anthracyclines / Q000008:administration & dosage / Q000494:pharmacology*; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000008:administration & dosage / Q000494:pharmacology*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism* / Q000601:surgery; D045744:Cell Line, Tumor; D017322:Clinical Trials, Phase II as Topic; D003520:Cyclophosphamide / Q000008:administration & dosage; D018572:Disease-Free Survival; D019008:Drug Resistance, Neoplasm; D015251:Epirubicin / Q000008:administration & dosage; D005472:Fluorouracil / Q000008:administration & dosage; D015870:Gene Expression / Q000187:drug effects; D019450:Genes, MDR / Q000187:drug effects*; D006801:Humans; D007150:Immunohistochemistry; D026901:Membrane Transport Proteins / Q000096:biosynthesis / Q000235:genetics; D000089762:Multidrug Resistance-Associated Protein 2; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000096:biosynthesis* / Q000235:genetics* / Q000378:metabolism; D020360:Neoadjuvant Therapy; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics
chemical_list: D018943:Anthracyclines; D003520:Cyclophosphamide; D015251:Epirubicin; D005472:Fluorouracil; D026901:Membrane Transport Proteins; D000089762:Multidrug Resistance-Associated Protein 2; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D012333:RNA, Messenger; C000715087:ABCC2 protein, human; C114462:multidrug resistance-associated protein 3; C421109:multidrug resistance-associated protein 1