Molecular Treatment of Different Breast Cancers

Breast cancer is subdivided into three types: hormone (estrogen and progesterone) receptor (ER and PR) positive, Her2-neu positive and triple negative breast cancers. In general, surgical and radiation treatments are similar, but drug treatment for different subtypes of breast cancers is different. Endocrine therapy (ET) is specifically used for the treatment of ER and PR positive breast cancers. This review discusses every aspect of endocrine therapy: ovarian suppression agents, selective estrogen receptor modulators (SERMs) and downregulators, and aromatase inhibitors (AIs). The most famous agents for the treatment of HER2 positive breast cancers are trastuzumab and its derivative Kadcyla (ado-trastuzumabemtansine). Other agents for the treatment of this subtype of breast cancers are also discussed. For the treatment of triple-negative breast cancers (TNBC) and other breast cancers, the following agents are discussed: anthracyclines and related regimens, taxanes, combination therapy of platinum with taxanes, combination therapy to counter drug resistance, ixabepilone and other epothilones, angiogenesis inhibitors. The lack of known specific molecular targets has promoted abundant research in order to find possible "vulnerabilities" in TNBC. For the first time, we propose thetranslocator protein (TSPO) 18 kDa as a potential target for TNBC. Furthermore, currently Photodynamic Therapy (PDT) is way under-explored for the treatment of breast cancers. In this review, PDT for the treatment of breast cancers is discussed. We also discuss imaging-guided therapy for breast cancers. Finally, from a perspective point of view, we call on the development of more potent agents for differentiation therapy.