 Natural killer, MK, cells are important components of the body's immune system, and they have been found to be effective at controlling tumor growth and metastases. They are able to directly kill cancerous cells without needing to be sensitized first, as well as release immunostimulatory cytokines such as interferon gamma, IFN, which helps to activate other parts of the immune system. Additionally, MK cells can also help to regulate cellular proliferation and angiogenesis, promote apoptosis, and enhance AG processing and presentation. However, MK cells often fail to function properly in cancer patients, and this limits their effectiveness in fighting cancer. Researchers are therefore exploring ways to manipulate MK cells so that they can be used in immunotherapies, such as antibody-based strategies and adoptive cell transfer. This article was authored by Australia Merial Levi, Maria Paula Robatti and Jose Mordo.