SPARC expression and prognostic value in non-small cell lung cancer

Secreted protein, acidic and rich in cysteine (SPARC) is expressed in numerous types of tumors and is suggested to have prognostic value. Moreover, because of its strong affinity for albumin, and hence albumin-bound drugs, SPARC has increasingly become a focus for research. In this study, we aimed to determine SPARC expression in patients with non-small cell lung cancer (NSCLC) and investigate the association of SPARC with disease prognosis. Tissue microarrays were constructed with specimens from 105 patients with NSCLC treated at Sun Yat-sen University Cancer Center, and immunohistochemical analysis was performed on these tissue microarrays to assess SPARC expression. Our results showed that SPARC expression status did not significantly relate with age, gender, and tumor stage. However, SPARC was expressed more frequently in squamous cell carcinoma than in adenocarcinoma (75% vs. 43.5%, P = 0.004). Patients with smoking history had higher SPARC expression than non-smokers (68.2% vs. 33.3%, P = 0.002). In both univariate and multivariate analyses, SPARC was a prognostic factor of overall survival (HR = 0.32; 95% CI: 0.16-0.65) but not disease-free survival. Our study indicates that SPARC expression is higher in squamous cell carcinoma than in adenocarcinoma in NSCLC. Most notably, SPARC can be used as a prognostic factor for NSCLC.