NK cellListen to pronunciation(… sel)A type of immune cell that has granules (small particles) with enzymes that can kill tumor cells or cells infected with a virus. An NK cell is a type of white blood cell. Also called natural killer cell and NK-LGL.Enlarge this image in new windowBlood cell development. A blood stem cell goes through several steps to become a red blood cell, platelet, or white blood cell. Search NCI's Dictionary of Cancer TermsStarts withContainsBrowse:ABCDEFGHIJKLMNOPQRSTUVWXYZ#