So the special thing about these natural killer cells is that they can bind and destroy these cancer cells regardless of whether or not they have the MHC complex on the membrane. So once again, natural killer cells are lymphocytes that are part of our innate immunity. Now, majority of the white blood cells of our immune system can only recognize an abnormal cell, such as a cancer cell if it contains an antigen that is bound onto the MHC, the major histocompatibility complex membrane protein. However, natural killer cells are the exception. They are unique because they do not require the presence of the major histocompatibility complex on the membrane of that particular abnormal cell. Interestingly, some infected or cancer cells sometimes are missing the MHC entirely from their membrane which makes them virtually invisible to all the other white blood cells of our body except these natural killer cells.