Disclosed herein are compositions and methods useful for the treatment of cancer, such as breast cancer. In some embodiments, the methods and compositions include human prolactin, or human prolactin in conjunction with a cytotoxic agent. In other embodiments, the methods and compositions include one or more of human prolactin, growth hormone and placental lactogen, or one or more of human prolactin, growth hormone and placental lactogen in conjunction with a cytotoxic agent. In some embodiments, the cytotoxic agent comprises a chemotherapeutic agent.
