title: A critical evaluation of loss of heterozygosity detected in tumor tissues, blood serum and bone marrow plasma from patients with breast cancer.
abstract: BACKGROUND
  The aim of the study was to perform a comparative analysis of LOH (loss of heterozygosity) in primary tumors as well as peripheral blood and bone marrow (BM) of patients with breast cancer (BCa).
  
  
  METHODS
  Performing PCR-based fluorescence microsatellite analysis and using a panel of seven polymorphic microsatellite markers, we compared the profiles of LOH in primary tumors, peripheral blood and BM plasma from patients with primary BCa (n = 40, stage M0) as well as tumor tissues and blood serum from metastatic BCa patients (n = 48, stage M1). During the course of systemic treatment blood samplings from 12 M0 and 16 M1 patients were at least once repeated.
  
  
  RESULTS
  The overall incidences of LOH in tumor tissues, blood and BM samples were 27.5%, 9.0% and 5.0%, respectively. The marker D3S1255 was the only one in the panel that showed similar frequencies of LOH ranging from 19.0 to 24.5% in tumor, blood and BM samples. Both M0 blood serum and BM plasma samples displayed the same rate of 19.0%, whereas tumor and M1 serum showed a rate of 24.5% and 24.0%, respectively, at this locus. This marker also showed the highest frequency of LOH in serum and BM samples, whereas in tumor samples LOHs at the markers D13S218 (38%) and D17S855 (36%) were more frequent. Statistical analysis of the tumor samples showed that occurrence of LOH at the markers D3S1255 (P < 0.04), D9S171 (P < 0.05) and D17S855 (P < 0.03) correlated with undifferentiated nuclear grade. Additionally, significant associations of the number of LOH recorded at D17S250 with estrogen receptor (P < 0.02), progesterone receptor (P < 0.03) expression and high proliferation score (Ki-67 expression, P = 0.009) were observed. In blood serum samples a relationship between positive lymph node status and LOH at the marker D3S1255 was revealed (M0 stage, P = 0.05; M0+M1 stage, P = 0.004).
  
  
  CONCLUSIONS
  Our study demonstrates heterogeneous profiles and low rates of LOH, particularly on free DNA in BM and blood samples. However, the significant associations of LOH with some risk factors and the demonstrated possibility of monitoring free DNA in patients undergoing systemic therapy suggest that LOH analysis may be developed into a useful diagnostic tool.
authors.affiliation: Institute of Tumor Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany. hschwarz@uke.uni-hamburg.de
authors.forename: Heidi
authors.initials: H
authors.lastname: Schwarzenbach
authors.forename: Volkmar
authors.initials: V
authors.lastname: Müller
authors.forename: Cord
authors.initials: C
authors.lastname: Beeger
authors.forename: Miriam
authors.initials: M
authors.lastname: Gottberg
authors.forename: Nicole
authors.initials: N
authors.lastname: Stahmann
authors.forename: Klaus
authors.initials: K
authors.lastname: Pantel
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000097:blood / Q000235:genetics*; D001853:Bone Marrow / Q000378:metabolism / Q000473:pathology*; D001943:Breast Neoplasms / Q000097:blood / Q000175:diagnosis / Q000235:genetics*; D016022:Case-Control Studies; D004273:DNA, Neoplasm / Q000097:blood* / Q000235:genetics; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D019656:Loss of Heterozygosity; D018895:Microsatellite Repeats / Q000235:genetics; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D011379:Prognosis
chemical_list: D014408:Biomarkers, Tumor; D004273:DNA, Neoplasm