Increased apoptosis and elevated Fas expression in circulating natural killer cells in gastric cancer patients

Background Immune cells undergo extensive apoptosis in patients with cancer, which may be related to immune evasion by cancerous cells. The present study was designed to investigate the relationship between natural killer (NK) cell apoptosis and Fas expression in gastric cancer patients. Methods NK cell apoptosis and Fas expression were evaluated by multicolor flow cytometry. Soluble Fas ligand (sFasL) was quantitated by enzyme-linked immunosorbent assay. Results The frequency of apoptotic NK cells in gastric cancer patients was significantly higher than in normal controls ( p = 0.0016). Moreover, their frequency was related to the progression of gastric cancer. Fas-positive NK cells were significantly more common in gastric cancer patients compared with normal controls ( p = 0.034). Furthermore, Fas expression was closely related to the frequency of NK cell apoptosis ( r = 0.6, p