Correlation between Cx37 and ALK expression and prognosis of elderly patients with non-small cell lung cancer

BACKGROUND: Non-small cell lung cancer (NSCLC) is one of the most common types of lung cancer, accounting for about 80% of lung cancer patients. At present, the main treatment for NSCLC patients is surgery, and the prognosis is not ideal. There is a lack of literature on the correlation between Cx37 and ALK expression and the prognosis of elderly NSCLC patients after surgery. Therefore, the aim of this study is to investigate the correlation between the expressions of Cx37 and ALK and the prognosis of elderly patients with NSCLC after surgery, and to provide data support for the clinical management of NSCLC patients. METHODS: One hundred twenty elderly patients with NSCLC who were hospitalized in our hospital from December 1, 2021 to August 1, 2023 were collected. The clinical data including gender, age, tumor diameter, tumor differentiation, TNM stage, lymph node metastasis, prognosis and survival rate were retrospectively analyzed. Immunohistochemical SP method was used to detect the expression of Cx37 and ALK protein in NSCLC tissues. Patient survival status and cause of death were systematically recorded during 2-year follow-up. Correlation analysis, Kaplan-Meier survival analysis and Cox regression models were used to evaluate the impact of ALK and Cx37 expression on disease-free survival (DFS) and overall survival (OS) during 2-year follow-up. Sensitivity analyses excluding non-tumor-related deaths were performed to validate cancer-specific prognostic significance. RESULTS: There was no significant difference in the expression of Cx37 protein in cancer tissues of elderly NSCLC patients with different age, gender and tumor diameter (P > 0.05). However, it was related to TNM stage, lymph node metastasis and tumor differentiation (P < 0.05). There was no significant difference in the expression of ALK protein in elderly NSCLC patients with different age, gender, tumor diameter and tumor differentiation degree (P > 0.05). It is related to TNM stage and lymph node metastasis (P < 0.05). ALK and Cx37 showed significant positive correlation (r = 0.412, P < 0.001). Among 45 deaths during follow-up, 38 (84.4%) were tumor-related and 7 (15.6%) were non-tumor-related. Cox regression analysis demonstrated that both ALK-positive (HR = 2.341 for DFS, HR = 2.687 for OS) and Cx37-positive expression (HR = 2.156 for DFS, HR = 2.423 for OS) were independent risk factors for poor prognosis. Sensitivity analysis excluding non-tumor-related deaths confirmed these findings (ALK: HR = 2.523, P = 0.001; Cx37: HR = 2.298, P = 0.003). Patients with co-expression of both markers had the worst survival outcomes. CONCLUSION: In conclusion, the expressions of ALK and Cx37 are closely related to the prognosis of elderly patients with NSCLC after surgery, with their co-expression providing enhanced prognostic stratification, which provides data support for the study of new molecular markers for elderly patients with NSCLC after surgery.