FCGR3A and neoplasm: Natural killer cells (NK cells) are population of tumour-antagonizing immune cells that mediate the immunosurveillance of the neoplasm and constitute large granular CD3−CD56+ lymphocytes that can be classified into two subpopulations, depending on their expression of surface markers CD16 and CD56 and they do not require prior sensitization or stimulation for their effector function.