Breast cancer is the most common malignancy in women worldwide. The risk of breast cancer in women increases with age,and this is partly attributable to the accumulation of genetic lesions. Growing evidence demonstrates the role played by epigenetic modifiers and the tumor microenvironment in contributing to the increased risk of breast cancer. Transcription factor activity is altered in numerous cancer types via various direct mechanisms including chromosomal translocations, gene amplification or deletion, point mutations and alteration of expression, as well as indirectly through non-coding DNA mutations that affect transcription factor binding.