Breast cancer is one of the most common types of cancer among women, and is the second leading cause of cancer death in women. In Portugal, for example, about 4,500 new cases of breast cancer are detected annually, and 1,500 women die of this disease. Although chemotherapy has been shown to be effective against this malignant neoplasm, depending on several factors (such as histology, degree and stage of disease, among others), there have been increasing cases of resistance to drugs used in current chemotherapy treatments.
