['To examine the expression of osteopontin (OPN) in patients with advanced non-small cell lung cancer (NSCLC), and to analyze the correlation of the expression level of OPN with response to platinum-based chemotherapy and the prognosis of NSCLC patients.', 'This retrospective study enrolled 92 patients with advanced NSCLC. All of the patients received platinum- based regimens as first-line chemotherapy. The expression of OPN in advanced NSCLC tissue was detected by immunohistochemistry. The associations between OPN expression with response to chemotherapy and the prognosis were analyzed by SPSS 17.0 statistical software.', "The positive expression rate of OPN in advanced NSCLC tissue was 36.9% (34/92). The positive expression rate of OPN was higher in patients ≥70 years old (65.2%;15/23) vs those aged <70 years (27.5%;19/69; p<0.05), which was also higher in patients with distant metastasis (51.9%;28/54) than that in patients without metastasis 15.8% (6/38) , the difference with statistically significant (p<0.05). Pearson's correlation analysis results showed that OPN expression was significantly correlated with age (r=0.338, p=0.001) , distant metastasis (r=0.368, p<0.001), curative effect of platinum-based regimen (r=0.403, p<0.001), progression-free survival/PFS (r=-0.486, p<0.001) and overall survival/OS (r=-0.552, p<0.001). Furthermore, the OPN expression was an independent predictor of PFS and OS for patients with advanced NSCLC after receiving platinum-based first-line chemotherapy (p<0.001)."] Is osteopontin expression associated with platinum-based chemotherapy response and prognosis of patients with advanced non small cell lung cancer?