One of the main causes of failure in the treatment of breast cancer is the intrinsic presence of, or development of, drug resistance by the cancer cells. Recent studies on the mechanisms of cancer drug resistance have yielded important information highlighting both how tumour cells may escape these therapeutic constraints and that drug resistance may further impinge on tumour cell functions that may ultimately promote an adverse cell phenotype. New targets have been identified with potential therapeutic applications in resistant breast cancer leading to the subsequent evaluation of...