title: Comparative analysis of loss of heterozygosity and expression profile in normal tissue, DCIS and invasive breast cancer.
abstract: BACKGROUND
  Ductal carcinoma in situ (DCIS) is considered to be related to the development of invasive breast cancer. The aim of molecular biological research of preinvasive breast lesion characteristics and comparison with normal tissues and tissue of invasive tumours is to identify patients at high risk of developing invasive tumour on the basis of already established preinvasive lesions, and thus influence clinical decision-making. The aim of our study was to analyse several key molecules involved in different cellular pathways important for cancer development and progression in different types of breast tissue and to describe similarities and differences between premalignant and malignant lesions.
  
  
  METHODS
  Genetic material isolated from both the tumour and healthy tissue was examined by loss of heterozygosity (LOH) analysis and real-time PCR using collagen 2A as a house-keeping gene.
  
  
  RESULTS
  We analysed 65 samples of healthy mammary gland, 25 DCIS and 42 invasive ductal breast cancer samples. We analysed the LOH in three genes: BRCA1, BRCA2 and p53; and the gene expression of the VEGF gene and Bcl-2 gene. LOH in the BRCA1 gene was present in 44.74% of invasive samples and in 8.69% of DCIS (p=0.026); LOH in the BRCA2 gene in 45.0% of invasive samples and in 9.52% of DCIS (p=0.036); LOH in the p53 gene in 32.5% of invasive samples and in 31.82% of DCIS (p=0.97). No LOH was observed in normal tissue samples. VEGF was overexpressed in 14.3% of invasive cancers and in 12.0% of DCIS. Overexpression of Bcl-2 was observed in 11.9% of invasive cancers and in 8.0% of DCIS.
  
  
  CONCLUSIONS
  We have confirmed that some of the molecular characteristics of DCIS are identical to those of invasive carcinoma. This approach could lead to the identification of molecular markers as indicators for the potential development of DCIS into invasive carcinoma or identification of DCIS subgroups with latent invasion.
authors.affiliation: Oncogynecologic Center, Department of Obstetrics and Gynecology, Charles University in Prague, First Faculty of Medicine and General University Hospital, Apolinarska 18, Prague 2, Czech Republic. michal.zikan@lf1.cuni.cz
authors.forename: Michal
authors.initials: M
authors.lastname: Zikan
authors.forename: Jan
authors.initials: J
authors.lastname: Bohm
authors.forename: David
authors.initials: D
authors.lastname: Pavlista
authors.forename: David
authors.initials: D
authors.lastname: Cibula
mesh_terms: D001943:Breast Neoplasms / Q000235:genetics* / Q000473:pathology; D018270:Carcinoma, Ductal, Breast / Q000235:genetics* / Q000473:pathology; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000235:genetics* / Q000473:pathology; D004252:DNA Mutational Analysis; D005260:Female; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D019398:Genes, BRCA1; D024522:Genes, BRCA2; D019254:Genes, bcl-2; D016158:Genes, p53; D006801:Humans; D019656:Loss of Heterozygosity / Q000235:genetics; D009361:Neoplasm Invasiveness