['A metaanalysis was performed to investigate the association between serum osteopontin (OPN) levels and the clinical pathological features in non-small cell lung cancer (NSCLC) patients.', 'A systematic literature search was performed to identify relevant studies published prior to September 2014 using PubMed and China National Knowledge Infrastructure databases. Data extracted from the selected studies were analyzed using statistical software.', 'Based on our stringent selection criteria only 10 studies contained a combined total of 1,135 NSCLC patients. Our metaanalysis results clearly showed a strong correlation between serum OPN levels and multiple tumor parameters, such as TNM stage, histologic grade, and lymph node metastasis in NSCLC (TNM stage: RR = 0.69, 95% CI 0.62-0.77, p < 0.001; histologic grade: RR = 1.24, 95% CI 1.04-1.48, p = 0.016; lymph node metastasis: RR = 1.69, 95% CI 1.48 - 1.93, p < 0.001).'] Do serum Osteopontin Levels Correlate with Clinical and Pathological Features in Non-Small Cell Lung Cancer?