To investigate whether lipid accumulation in NK cells have functional consequences, Msr1+/Bodipy+ vs. Msr1−/Bodipy−, CD36+/Bodipy+ vs. CD36−/Bodipy−, and CD68+/Bodipy+ vs. CD68−/Bodipy− NK cells (NK1.1+/CD3−) were flow sorted from spleens of surgery-treated B6-B16 mice and used as effector cells to lyse chromium-labelled YAC-1 tumor targets in an ex vivo NK cell cytotoxicity assay. The gene discussed is CD68; the disease is neoplasm.