Background: Postoperative radiotherapy (PORT) is commonly used to treat patients with resected stage III non-small cell lung cancer (NSCLC), but its effectiveness remains uncertain. This retrospective cohort study aimed to investigate the impact of PORT on overall survival (OS) and evaluate its heterogeneity among subgroups of patients.Methods: A total of 6305 patients with resected stage III NSCLC were included in this study from the Surveillance, Epidemiology, and End Results (SEER) database. Propensity score matching was conducted to balance baseline characteristics between the patients who received PORT and those who did not. OS was used as the primary outcome. Subgroup analysis was performed to identify which patient subgroups might benefit more from PORT.Results: Overall, no significant difference was observed in OS between the 2 groups with or without propensity score matching. However, subgroup analysis demonstrated that PORT improved OS in patients with certain characteristics, including stage IIIA/ N2, stage IIIB, squamous cell carcinoma, tumor grade III-IV, or lymph node ratio (LNR) > 1/3. Multivariate analysis showed that several variables were associated with adverse prognostic factors for OS, such as marital status (others), race (white), male gender, squamous cell carcinoma, elderly age, advanced stage, poor histological differentiation grade, high LNR, and not receiving chemotherapy. Conclusion:In patients with resected stage III NSCLC, PORT may not be beneficial for all patients. However, it may improve survival time in certain patient subgroups, such as those with stage IIIA/N2, stage IIIB, squamous cell carcinoma, tumor grade III to IV, or LNR > 1/3. These findings provide important information for clinical decision-making and future research regarding the use of PORT in patients with resected stage III NSCLC.Abbreviations: LNR = positive to sampled lymph node ratio, NSCLC = non-small cell lung cancer, MST = median survival time, OS = overall survival, PORT = postoperative radiotherapy, PSM = propensity score matching, RCT = randomized controlled trial, SEER = surveillance, epidemiology, and end results.

Background: Lung adenocarcinoma, as a common histological type in lung cancer, the overall survival is very low, and the prognosis is poor because it is difficult to find and easily recurs. Therefore, this study aimed to explore the role of the secreted protein beta-1,3-N-acetylglucosaminyltransferase 3 (B3GNT3) in the development of lung adenocarcinoma and to evaluate its potential significance for early clinical biomarker screening. Methods:The mRNA expression profiles of patients with lung adenocarcinoma and normal controls were analyzed via The Cancer Genome Atlas (TCGA) database. Serum samples of clinical lung cancer patients and healthy people were obtained, and the differences in B3GNT3 expression in different stages of lung adenocarcinoma and in healthy tissues were compared. Kaplan-Meier (K-M) curves were drawn to clarify the influence of high and low expression of B3GNT3 on the prognosis of patients. Peripheral blood samples from patients with lung adenocarcinoma and healthy people were obtained clinically, and receiver operating characteristic (ROC) curves were drawn to clarify the sensitivity and specificity of B3GNT3 expression for the diagnosis of lung adenocarcinoma. Lung adenocarcinoma cells were cultured in vitro, the expression of B3GNT3 was knocked down by lentivirus infection. The expression of the apoptosis-associated genes was detected by reverse transcription-polymerase chain reaction (RT-PCR). Results:The secreted protein B3GNT3 is significantly differentially expressed in the serum of patients with lung adenocarcinoma versus normal controls. Subgroup analysis according to lung adenocarcinoma clinical stage showed that the higher the clinical stage of lung adenocarcinoma was, the higher the B3GNT3 expression. Enzyme-linked immunosorbent assay (ELISA) revealed that B3GNT3 expression was significantly increased in the serum of patients with lung adenocarcinoma and significantly decreased after surgery. By inhibiting programmed cell death-ligand 1 (PD-L1), the level of apoptosis was significantly increased and the proliferative capacity was significantly inhibited. In contrast, the level of apoptosis was significantly increased and the proliferation ability was significantly inhibited after simultaneous overexpression of B3GNT3 and inhibition of PD-L1.Conclusions: High expression of the secreted protein B3GNT3 in lung adenocarcinoma is closely related to prognosis and can serve as a potential biological marker for the early screening of lung adenocarcinoma.