title: Heterogeneous expression of tumor-associated genes in disseminated breast cancer cells.
abstract: BACKGROUND
  Gene expression profiles were determined to demonstrate heterogeneity of viable disseminated tumor cells (DTC) in the blood of breast cancer patients.
  
  
  METHODS
  All patients (n = 48) suffered from metastatic disease (M1) and were treated with chemotherapy and/or Herceptin, respectively. Blood samples were analyzed by a DTC detection assay consisting of immunomagnetic tumor cell selection combined with expression profiling of the tumor-associated transcripts GA733-2, MUC-1, HER-2 and Claudin-7. In addition, the correlation of HER-2 expression in DTC with histopathologically determined HER-2 status in distant metastases and primary tumors in selected cases was investigated.
  
  
  RESULTS
  DTC were detected in 69% (p < 0.0001) of breast cancer patients. The expression profiles were shown to be heterogeneous within different patients and even within the follow-up period of patients, reflecting the expected heterogeneity of DTC. Furthermore, preliminary results showed a correlation between HER-2 gene expression in DTC and HER-2 overexpression in tumor tissue of distant metastases.
  
  
  CONCLUSIONS
  The results suggest a clinical value of the DTC detection assay with respect to a more precise characterization of individual cancer disease and selection for therapy. More emphasis should be placed on HER-2 expression in DTC as a possible precursor of distant metastases.
authors.affiliation: AdnaGen AG, Ostpassage 7, D-30853 Langenhagen, Germany.
authors.forename: Veit
authors.initials: V
authors.lastname: Zieglschmid
authors.forename: Christiane
authors.initials: C
authors.lastname: Hollmann
authors.forename: Bertha
authors.initials: B
authors.lastname: Gutierrez
authors.forename: Andreas
authors.initials: A
authors.lastname: Krehan
authors.forename: Sepp
authors.initials: S
authors.lastname: Kaul
authors.forename: Oliver
authors.initials: O
authors.lastname: Böcher
mesh_terms: D000951:Antigens, Neoplasm / Q000235:genetics / Q000378:metabolism; D001943:Breast Neoplasms / Q000235:genetics* / Q000473:pathology; D015815:Cell Adhesion Molecules / Q000235:genetics / Q000378:metabolism; D057167:Claudins; D000071858:Epithelial Cell Adhesion Molecule; D005260:Female; D015870:Gene Expression; D020869:Gene Expression Profiling; D018734:Genes, erbB-2; D006801:Humans; D018189:Immunomagnetic Separation / Q000379:methods*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D008875:Middle Aged; D018396:Mucin-1 / Q000235:genetics / Q000378:metabolism; D009362:Neoplasm Metastasis / Q000235:genetics; D009360:Neoplastic Cells, Circulating / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012680:Sensitivity and Specificity
chemical_list: D000951:Antigens, Neoplasm; C473255:CLDN7 protein, human; D015815:Cell Adhesion Molecules; D057167:Claudins; C499379:EPCAM protein, human; D000071858:Epithelial Cell Adhesion Molecule; D008565:Membrane Proteins; D018396:Mucin-1; D012333:RNA, Messenger