Epigenetic modifications of p16, E-cadherin, RAR beta and DAPK gene promoters in breast cancer

The breast cancer is the result of multiple associations of genetic and epigenetic alterations, which lead to overexpression of the proto-oncogenes and loss of expression of tumor suppressor genes. Such new expression patterns determine the cell genetic reprogramming results in the oncogenesis process and therefore may represent possible important markers for diagnostic and prognostic in cancer therapy. The epigenetic process is frequently associated with the aberrant silencing of tumor suppressor genes through the CpG islands located in their promoter region. These regions are normally unmethylated while in tumor cells are abnormally hypermethylated and associated with transcriptional silencing. Such local hypermethylation processes represent frequently an alternative mechanism for mutations of tumor suppressor genes, being an early and ordinary process for many tumor types, including breast cancer. The aim of this study is to analyze the promoter methylation pattern of some tumor suppressor genes (p16, E-cadherin, RARβ and DAPK) in invasive ductal breast cancers, in order to identify new molecular markers for diagnosis and prognosis.