Diagnostic Value of CCL2 and CCR2 in Pleural Effusion for Distinguishing Lung Cancer Histological Subtypes: A Retrospective Study

OBJECTIVE: This study evaluated the diagnostic value of C-C motif chemokine ligand 2 (CCL2) and C-C chemokine receptor type 2 (CCR2) in pleural effusions for distinguishing histological subtypes of lung cancer (LC). METHODS: A retrospective cohort study was conducted on 96 cases of squamous cell carcinoma (LUSC), 206 cases of lung adenocarcinoma (LUAD), and 53 cases of small cell LC (SCLC). A control group of 102 patients with parapneumonic effusion was selected. CCL2 and CCR2 levels in pleural effusions were measured. Pearson correlation analysis and receiver operating characteristic curve analysis were conducted. RESULTS: Pleural effusion CCL2 and CCR2 levels were higher in advanced LC than in parapneumonic effusion, and the changes in these two levels showed a moderate positive correlation (p < 0.001). CCL2 and CCR2 levels in pleural effusions were elevated in LUAD patients compared to LUSC and SCLC patients (p < 0.01), with SCLC patients having higher levels than LUSC patients (p < 0.01). The AUC for the combined CCL2 and CCR2 panel was higher than that for CCL2, CCR2, carcinoembryonic antigen, and cytokeratin fragment antigen 21-1 tested individually (all p < 0.05). CONCLUSION: Patients with advanced LC exhibit elevated CCL2 and CCR2 levels in pleural effusions. Combined detection of these two markers has some diagnostic value in distinguishing between LUAD and LUSC, serving as a valuable supplement to histopathological examination; however, clinical application should involve a comprehensive assessment in conjunction with other auxiliary tests. These markers have limited value in distinguishing between SCLC and NSCLC.