Potential predictive value of change in inflammatory cytokines levels subsequent to initiation of immune checkpoint inhibitor in patients with advanced non-small cell lung cancer

For a definite indication for immunotherapy, finding appropriate biomarkers that are predictive of treatment responses is necessary. Inflammatory cytokines which play critical roles in immunity against infectious sources or cancer cells are suggested to activate immune cells after initiation of immune checkpoint inhibitors (ICI). Through activation of immune cells such as T cells, natural killer cells, macrophages, or tumor infiltrating dendritic cells, inflammatory cytokines usually increase after programmed death (PD)-1/PD-L1 axis blockade. There have been several studies evaluating the predictive value of early changes in inflammatory cytokines in non-small cell lung cancer (NSCLC) patients undergoing immunotherapy. In this mini-review, we went through recent articles on potential blood level values of inflammatory cytokines in NSCLC patients receiving ICI and their early change around commencement of ICIs in predicting response to treatment and disease progression. The studies evaluated cytokines including interleukin (IL)-2, 6, 8, interferon (IFN)-γ, and tumor necrosis factor (TNF)-α for predictability for responses to ICI. A combination cytokine panel can help predict the response and prognosis of patients with NSCLC who are receiving ICI treatment. Furthermore, a more individualized ICI treatment will be available if responses and change in tumor burden can be predicted. However, most of the studies on cytokines in NSCLC patients receiving ICIs had a small number of patients, and the heterogeneous measurement time points. Nevertheless, cytokines such as IL-8 and IFN- γ have considerable potential predictive value for immunotherapy response, which is worthy of further studies. To utilize blood cytokines levels as biomarkers for immunotherapy, a larger study with uniform measurement protocol is necessary.