The intrinsic anti-tumor activity of NK-92 cells observed in the background levels of CD107a surface expression in mock NK-92 cells, which was slightly more pronounced against the NK-sensitive U266 cells compared to the NK-resistant Daudi cells (25.8 ± 3.3% and 18.4 ± 4% CD107a+, respectively). The gene discussed is LAMP1; the disease is neoplasm.