title: Gene expression profiles derived from fine needle aspiration correlate with response to systemic chemotherapy in breast cancer.
abstract: BACKGROUND
  Drug resistance in breast cancer is a major obstacle to successful chemotherapy. In this study we used cDNA microarray technology to examine gene expression profiles obtained from fine needle aspiration (FNA) of primary breast tumors before and after systemic chemotherapy. Our goal was to determine the feasibility of obtaining representative expression array profiles from limited amounts of tissue and to identify those expression profiles that correlate with treatment response.
  
  
  METHODS
  Repeat presurgical FNA samples were taken from six patients who were to undergo primary surgical treatment. Additionally, a group of 10 patients who were to receive neoadjuvant chemotherapy underwent two FNAs before chemotherapy (adriamycin 60 mg/m2 and cyclophosphamide 600 mg/m2) followed by another FNA on day 21 after the first cycle. Total RNA was amplified with T7 Eberwine's procedure and labeled cDNA was hybridized onto a 7600-feature glass cDNA microarray.
  
  
  RESULTS
  We identified candidate gene expression profiles that might distinguish tumors with complete response to chemotherapy from tumors that do not respond, and found that the number of genes that change after one cycle of chemotherapy was 10 times greater in the responding group than in the non-responding group.
  
  
  CONCLUSIONS
  This study supports the suitability of FNA-derived cDNA microarray expression profiling of breast cancers as a comprehensive genomic approach for studying the mechanisms of drug resistance. Our findings also demonstrate the potential of monitoring post-chemotherapy changes in expression profiles as a measure of pharmacodynamic effect and suggests that these approaches might yield useful results when validated by larger studies.
authors.affiliation: Division of Clinical Sciences, Advanced Technology Center, National Cancer Institute, National Institutes of Health, Gaithersburg, USA. christos.sotiriou@bordet.be
authors.forename: Christos
authors.initials: C
authors.lastname: Sotiriou
authors.forename: Trevor J
authors.initials: TJ
authors.lastname: Powles
authors.forename: Mitch
authors.initials: M
authors.lastname: Dowsett
authors.forename: Amir A
authors.initials: AA
authors.lastname: Jazaeri
authors.forename: Andrew L
authors.initials: AL
authors.lastname: Feldman
authors.forename: Laura
authors.initials: L
authors.lastname: Assersohn
authors.forename: Chandramouli
authors.initials: C
authors.lastname: Gadisetti
authors.forename: Steven K
authors.initials: SK
authors.lastname: Libutti
authors.forename: Edison T
authors.initials: ET
authors.lastname: Liu
mesh_terms: D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D001707:Biopsy, Needle; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000235:genetics* / Q000473:pathology; D003520:Cyclophosphamide / Q000008:administration & dosage; D004317:Doxorubicin / Q000008:administration & dosage; D019008:Drug Resistance, Neoplasm / Q000235:genetics; D005260:Female; D020869:Gene Expression Profiling / Q000592:standards*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D020411:Oligonucleotide Array Sequence Analysis / Q000592:standards*; D011237:Predictive Value of Tests; D016896:Treatment Outcome
chemical_list: D004317:Doxorubicin; D003520:Cyclophosphamide