The worldwide incidence of breast cancer affects 1.2 million women each year. In contrast to the high occurrence of this malady, a decline in mortality is reported among industrialized countries. In this respect, both awareness campaigns and substantial progress achieved in therapy and diagnosis allowed for the enhancement of the survival rate in patients with breast cancer. Undoubtedly, oncology research programs played a relevant role in the improvement of therapeutics and diagnostics for breast cancer. Major strides were reported, especially over the last decade and a half, in better understanding molecular and cellular biology events involved in breast cancer pathogenesis and progression of the disease. However, therapeutic approaches for the treatment of patients with breast cancer need further improvement. Therapeutic interventions can chronically compromise both the state of health and quality of life of breast cancer survivors. In addition, current therapeutic approaches have not significantly improved the survival rate in patients with metastatic disease. On these grounds, it is necessary to develop more efficient therapeutics and diagnostic tools, which can improve the health and quality of life of breast cancer survivors and increase the survival rate in patients with metastatic disease. In this respect, the field of cancer research has placed a particular emphasis on the elucidation of genetic and epigenetic alterations that may lead to the pathogenesis of breast cancer and contribute to its progression.