Preoperative and postoperative NK (Natural killer) cell activation and relationship with the tumor micro environment in resected non-small cell lung cancer cases.

Lung cancer is the most common cause of death from cancer worldwide. The most common cause in its etiology is the use of tobacco and tobacco products. Non-small cell lung cancers (NSCLC) constitute approximately 80-85% of lung cancers. If NSCLCs are detected at an early stage and operated, their five-year survival reaches 60-70%. Unfortunately, detection of lung lesions at an early stage is difficult because of late symptoms. Therefore, the number of inoperable and advanced metastatic patients is high. These patients are referred for treatment, which may be chemotherapy, radiotherapy, targeted therapy, immunotherapy, or a combination of several. Studies on alternative treatments are continuing due to the serious complications of chemotherapy and radiotherapy, which are accepted as the main treatment methods in patients who do not have a chance for surgery, to reduce the quality of life of patients, and to not achieve the desired level of treatment success. The most important part of this is the studies on immunotherapy. As with all treatment methods, the most important factor that reduces the chance of success in immunotherapy treatments and ensures the development of resistance is the micro-environment (TME) formed by the tumor. It has been shown in various solid tumors that natural killer (NK) cells achieve successful results against TME due to their cytotoxic effect without prior sensitization, being directed by activating-inhibitory signals, being produced in high amounts in a short time, and being allogeneic. In this study, NK cell activation in venous blood before and after surgery in patients who underwent resection for NSCLC and immunohistochemically NK cells in TME in resection material were examined. It was aimed to determine whether there is a change in NK cell activation after the tumor and its microenvironment are removed from the body in NSCLC, and if there is a change, its relationship with TME. According to the data obtained, a significant decrease in NK activation was observed in the first week after surgery compared to the preoperative period, and a significant increase was observed in the third week after surgery compared to the first week. In the third week after surgery, an increase was observed compared to the pre-surgery, but it was not found significant. No significant correlation was found between NK cell scoring with immunohistochemical staining and NK activation from venous blood in TME. It is thought that the tumor and its microenvironment suppress NK cell activation in NSCLCs, and it is predicted that NK-focused immunotherapies will affect the success rate.