An overview of new therapeutic approaches for the treatment of metastatic breast cancer

Metastatic cancer, also known as stage-IV cancer, is the process by which cancer cells move to different areas of the body, contributing to the majority of cancer deaths. Immunotherapy, a novel treatment for breast cancer, has emerged as a new option due to the discovery of immune checkpoint inhibitors and a better understanding of how cancer cells evade the immune system. However, single-drug treatments using monoclonal antibodies against programmed death-1 and PD-L1 have not shown much success in treating metastatic breast cancer patients. The development of immunotherapy and molecularly targeted treatment combinations for metastatic breast cancer is gaining attention. This Personal View examines the safety and effectiveness of immunotherapeutic approaches when used in conjunction with chemotherapy, radiotherapy, angiogenesis inhibitors, inhibitors of cyclin-dependent kinases 4 and 6, HER2-targeted therapy, poly (ADP-ribose) polymerase inhibitors, and other treatments. Gene therapy, a new scientific revolution, has been heralded as the next great revolution in biomedicine, but its therapeutic efficacy is severely compromised by extracellular and intracellular hurdles during gene transport.