Circulatory miRNA-155, miRNA-21 target PTEN expression and activity as a factor in breast cancer development.

Breast cancer is a complex disease with multiple factors involved in its pathophysiological development. genetic mutations of BRCA1, BRCA2 and p53 are among the most well-studied factors. The role of other genetic factors like altered expression profiles, SNPs in the regulatory regions of different genes or epigenetic factors like promoter methylation and histone modifications are also well studied but no solid understanding is available on distinct key players triggering malignancy in breast cancer, (Phosphatase and tensin homolog) PTEN is known to be a crucial tumor suppressor as it has been reported to be missing or abnormally expressed in many cancer cells.