Targeted drug delivery for breast cancer treatment

Breast cancer is the commonest type of malignant tumor in women, comprising of about 30% of all cancers in women worldwide. In the past decades, the mortality of breast cancer patients has significantly been reduced due to the adoption of periodic breast cancer screening and the emergence of various treatments, such as radiotherapy, chemotherapy, and surgery. Currently, chemotherapy is one of the most effective treatments for breast cancer. Its side effects, however, pose a long-term challenge on a patient's health. Thus, it is highly desirable to develop new therapies that can specifically target carcinoma cells without damaging normal and healthy cells. Tremendous efforts have been made to develop targeted drug delivery systems for breast cancer treatment. In this review, we intend to systematically examine recent progresses made along these directions. We highlighted various delivery carriers designed for directing the diffusion of therapeutic agents inside tumors to kill or suppress breast cancer cells. These carriers include molecular-recognitionelement modified anticancer agents, stem cells that have tropism to breast cancers, nanoparticle-based anticancer drugs, and anticancer peptides. In particular, we discussed recent patents on the new targeted therapeutic delivery systems, with an emphasis on triple-negative breast cancer therapies.