title: Heterogeneity of breast cancer metastases: comparison of therapeutic target expression and promoter methylation between primary tumors and their multifocal metastases.
abstract: OBJECTIVE
  A comprehensive comparison of biomarker expression between patients' primary breast carcinoma (PBC) and their metastatic breast carcinomas (MBC) has not been done.
  
  
  METHODS
  We did rapid autopsies (postmortem intervals, 1-4 hours) on 10 consenting patients who died of MBC. We constructed single-patient tissue microarrays from the patients' archived PBC and multiple different MBCs harvested at autopsy, which were immunohistochemically labeled for multiple biomarkers. Methylation of multiple gene promoters was assessed quantitatively on dissected PBC and MBC samples.
  
  
  RESULTS
  Extensive heterogeneity was observed between PBC and their paired MBC, as well as among multiple MBC from the same patient. Estrogen and progesterone receptors tended to be uniformly down-regulated in metastases. E-cadherin was down-regulated in a subset of the MBC of one case. Variable overexpression in MBC compared with the PBC was observed for cyclooxygenase-2 (five cases), epidermal growth factor receptor (EGFR; four cases), MET (four cases), and mesothelin (four cases). No case strongly overexpressed HER-2/neu by immunohistochemistry, but eight cases showed variable protein expression ranging from negative to equivocal (2+) in different MBC. In one case, variable low-level HER-2/neu gene amplification was found. EGFR and MET overexpression were restricted to the four basal-type cancers. EGFR protein overexpression did not correlate with EGFR gene amplification. Multigene promoter hypermethylation of RASSF1a, HIN1, cyclin D2, Twist, estrogen receptor alpha, APC1, and RARbeta was overall very similar in the PBC and all MBCs in all cases.
  
  
  CONCLUSIONS
  Therapeutic targets identified in the PBC or even some MBC may not reflect targets present in all metastatic sites.
authors.affiliation: Department of Pathology, Johns Hopkins Medical Institutions, Baltimore, Maryland 21231, USA.
authors.forename: Julie M
authors.initials: JM
authors.lastname: Wu
authors.forename: Mary Jo
authors.initials: MJ
authors.lastname: Fackler
authors.forename: Marc K
authors.initials: MK
authors.lastname: Halushka
authors.forename: Diana W
authors.initials: DW
authors.lastname: Molavi
authors.forename: M Evangeline
authors.initials: ME
authors.lastname: Taylor
authors.forename: Wei Wen
authors.initials: WW
authors.lastname: Teo
authors.forename: Constance
authors.initials: C
authors.lastname: Griffin
authors.forename: John
authors.initials: J
authors.lastname: Fetting
authors.forename: Nancy E
authors.initials: NE
authors.lastname: Davidson
authors.forename: Angelo M
authors.initials: AM
authors.lastname: De Marzo
authors.forename: Jessica L
authors.initials: JL
authors.lastname: Hicks
authors.forename: Dhananjay
authors.initials: D
authors.lastname: Chitale
authors.forename: Marc
authors.initials: M
authors.lastname: Ladanyi
authors.forename: Saraswati
authors.initials: S
authors.lastname: Sukumar
authors.forename: Pedram
authors.initials: P
authors.lastname: Argani
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis*; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D019175:DNA Methylation; D005260:Female; D015870:Gene Expression; D006801:Humans; D007150:Immunohistochemistry; D008875:Middle Aged; D009362:Neoplasm Metastasis / Q000235:genetics / Q000473:pathology*; D011401:Promoter Regions, Genetic; D046888:Tissue Array Analysis
chemical_list: D014408:Biomarkers, Tumor