Cytoplasmic clusterin expression is associated with longer survival in patients with resected non-small cell lung cancer

Background: Clusterin is a glycoprotein that has been implicated in many processes, including apoptosis, cell cycle regulation, and DNA repair. Previous studies have examined the prognostic value of clusterin expression in various malignancies. In the present study, we examined clusterin staining in tumors resected from patients with non-small cell lung cancer (NSCLC). Materials and Methods: Tumor specimens were obtained for 113 patients with completely resected NSCLC from paraffin-embedded tissue microarrays and stained with an antibody specific for clusterin. Staining patterns were observed and graded based on intensity and then correlated with clinical data. Results: Positive cytoplasmic clusterin staining was observed in 44 patients, and weak/negative staining was observed in 62 patients. Patients who had tumors that stained positive for cytoplasmic clusterin had significantly longer survival in multivariate analysis (hazard ratio 0.487, 95% confidence interval 0.27-0.89). A correlation was also observed for recurrence-free survival, which approached statistical significance (hazard ratio 0.345, 95% confidence interval 0.12-1.02). In univariate analysis, patients with clusterin-positive tumors had a 63% 3-year survival, whereas patients with clusterin-negative tumors had a 42% 3-year survival (P = 0.0108); clusterin-positive tumors also had significantly less recurrence W = 0.0231). Conclusions: Cytoplasmic clusterin staining is present in a substantial number of NSCLC tumors and may be a biomarker for longer survival in patients with surgically resected NSCLC.