Quantitative assessment of DNA hypermethylation in the inflammatory and non-inflammatory breast cancer phenotypes

Cancer Biol Ther. 2009 Dec;8(23):2252-9. doi: 10.4161/cbt.8.23.10133. Epub 2009 Dec 19.

Abstract

In this study, a comparative quantitative methylation profiling of inflammatory breast cancer (IBC) and non-IBC was set up for the identification of tumor-specific methylation patterns. Methylation ratios of six genes (DAPK, TWIST, HIN-1, RASSF1A, RARbeta2 and APC) were measured in benign breast tissues (n = 9) and in tumor samples from non-IBC (n = 81) and IBC (n = 19) patients using quantitative methylation-specific PCR. Median methylation ratios observed in breast cancer (n = 100) were significantly higher than those observed in benign breast tissues for five of six genes (TWIST, HIN-1, RASSF1A, RARbeta2 and APC). Only one of the individual genes studied, RARbeta2, showed differential methylation ratios in IBC and non-IBC (p = 0.016). Using the maximal methylation ratio observed in benign breast tissue as a threshold, the methylation frequency of two genes, RARbeta2 and APC, was significantly increased in IBC (n = 19) when compared to non-IBC (n = 81): 53 vs. 23% for RARbeta2 (p = 0.012) and 84 vs. 54% for APC (p = 0.017). Using hierarchical clustering, methylation patterns could not classify breast cancers according to their phenotype. The finding of differential frequencies of methylation in IBC and non-IBC for two out of six genes suggests that gene-specific patterns of methylation could provide a basis for molecular classification of IBC. Testing for additional genes could help to define the IBC phenotype based on patterns of aberrant gene promoter methylation.

Publication types

  • Comparative Study

MeSH terms

  • Adenomatous Polyposis Coli Protein / genetics
  • Adult
  • Aged
  • Aged, 80 and over
  • Apoptosis Regulatory Proteins / genetics
  • Biomarkers, Tumor / genetics*
  • Biomarkers, Tumor / metabolism
  • Breast / metabolism
  • Breast / pathology*
  • Breast Neoplasms / genetics*
  • Breast Neoplasms / pathology
  • Calcium-Calmodulin-Dependent Protein Kinases / genetics
  • CpG Islands
  • Cytokines / genetics
  • DNA Methylation*
  • Death-Associated Protein Kinases
  • Female
  • Gene Expression Regulation, Neoplastic
  • Humans
  • Inflammation / genetics*
  • Inflammation / metabolism
  • Inflammation / pathology
  • Middle Aged
  • Neoplasm Invasiveness
  • Nuclear Proteins / genetics
  • Phenotype
  • Polymerase Chain Reaction
  • Prognosis
  • Promoter Regions, Genetic / genetics
  • Receptors, Retinoic Acid / genetics
  • Tumor Suppressor Proteins / genetics
  • Twist-Related Protein 1 / genetics

Substances

  • Adenomatous Polyposis Coli Protein
  • Apoptosis Regulatory Proteins
  • Biomarkers, Tumor
  • Cytokines
  • Nuclear Proteins
  • RARB2 protein, human
  • RASSF1 protein, human
  • Receptors, Retinoic Acid
  • SCGB3A1 protein, human
  • TWIST1 protein, human
  • Tumor Suppressor Proteins
  • Twist-Related Protein 1
  • Death-Associated Protein Kinases
  • Calcium-Calmodulin-Dependent Protein Kinases