Advances in natural killer cell therapies for breast cancer

Breast cancer (BC) is the most common cause of cancer death in women. According to the American Cancer Society's yearly cancer statistics, BC constituted almost 15% of all the newly diagnosed cancer cases in 2022 for both sexes. Metastatic disease occurs in 30% of patients with BC. The currently available treatments fail to cure metastatic BC, and the average survival time for patients with metastatic BC is approximately 2 years. Developing a treatment method that terminates cancer stem cells without harming healthy cells is the primary objective of novel therapeutics. Adoptive cell therapy is a branch of cancer immunotherapy that utilizes the immune cells to attack cancer cells. Natural killer (NK) cells are an essential component of innate immunity and are critical in destroying tumor cells without prior stimulation with antigens. With the advent of chimeric antigen receptors (CARs), the autologous or allogeneic use of NK/CAR-NK cell therapy has raised new hopes for treating patients with cancer. Here, we describe recent developments in NK and CAR-NK cell immunotherapy, including the biology and function of NK cells, clinical trials, different sources of NK cells and their future perspectives on BC.