The importance of alterations in innate lymphoid cell subsets in patients with non-small cell lung cancer and their role in tumorigenesis

Objective. Non-small cell lung cancer (NSCLC) is one of the leading causes of cancer-related morbidity and mortality. Diverse functions of innate lymphoid cells (ILCs) and NK cell subsets are investigated thoroughly in cancer immunotherapy. ILC and recently described NK cell subsets in NSCLC patients’ blood samples and tumor draining lymph nodes were investigated. Methods. The study included chemotherapy and/or radiotherapy-naive NSCLC patients with clinical stage T1-4N0-2M0 who underwent video-assisted mediastinal lymphadenectomy and 14 healthy controls. Mononuclear cells were isolated from peripheral blood of both groups and mediastinal lymph nodes of NSCLC patients. NK cells and ILC subsets were analyzed by flow cytometry. Results. Total NK cells are shown to be increased in peripheral blood of NSCLC patients compared to lymph nodes while the ratio of CD56dimCD16- exhausted NK cells is higher in lymph nodes than in blood samples of NSCLC patients. Compared to control group, peripheral blood ILC1 cells were lower in NSCLC patients, however ILC2 and ILC3 cells were significantly increased. However, mediastinal lymph nodes of NSCLC patients had decreased ratio of ILC2 and increased ratio of ILC3 cells than in peripheral blood of patients. NSCLC patients had significantly increased ratio of NKp44-ILC3 cells and decreased ratio of NKp44+ILC3 in lymph nodes. Conclusion. Decreased ratio of ILC1 cells is an important indicator of impaired anti-tumoral response. Increased in the ratio of NKp44-ILC3 cells in NSCLC patients may potentially contribute to tumor progression. These findings highlight the distinct roles of ILCs, which play a pivotal role in the pathogenesis of lung cancer.