RESUMO
BACKGROUND AND AIM: We aimed to measure the natural killer (NK) cell activity and pro-inflammatory cytokine levels in the peripheral blood of pancreatic cancer patients and investigate the correlation of NK cell activity and cytokines with cancer status and clinical outcomes. METHODS: We prospectively enrolled patients who were pathologically diagnosed with pancreatic ductal adenocarcinoma (PDAC) between 2016 and 2017 at a tertiary hospital in Seoul, South Korea. As a control group, healthy participants were enrolled by mobile application recruitment. RESULTS: A total of 203 patients were enrolled for this study (PDAC, n = 102; healthy participants, n = 101). The peripheral blood NK cell activity of PDAC patients was significantly lower than that of healthy participants (median level, 95 pg/mL vs 2000 pg/mL, P < 0.001), and decreased NK cell activity was correlated to poor clinical outcome in terms of response to chemotherapy, tumor progression, and survival. The pro-inflammatory cytokine interleukin-6 had a strong negative correlation with NK cell activity. CONCLUSIONS: In pancreatic cancer patients, NK cell activity decreased as cancer progressed, and decreased NK cell activity was associated with poor clinical outcomes.