Heat shock protein 90-β over-expression is associated with poor survival in stage I lung adenocarcinoma patients

Heat shock protein 90-beta (Hsp90-β) is associated with cell proliferation, differentiation and apoptosis and has been investigated as a prognostic factor in many cancers. However, Hsp90-β protein expression in lung adenocarcinoma (ADC) has not been thoroughly elucidated. The aim of this study was to determine the relationship between Hsp90-β expression, clinicopathological parameters and prognosis in lung adenocarcinomas. Seventy-five surgically resected lung adenocarcinomas and matched normal lung tissue samples were obtained to construct a tissue microarray (TMA), including 44 stage IA-IB cases. Then, Hsp90-β protein expression level in lung tissue was evaluated by immunohistochemistry. Kaplan-Meier survival analysis with a Log-rank significance test was used to estimate the survival differences among subgroups according to Hsp90-β expression in lung ADC tissues using SigmaPlot/SigmaStat v10 and 3.5, respectively. Hsp90-β protein expression was significantly upregulated in lung ADC tissues compared to that in the matched normal alveoli (P<0.001) and was associated with tumor differentiation (P<0.001). Furthermore, Hsp90-β over-expression was correlated with poor survival in stage I patients (P=0.026). Increased Hsp90-β expression was associated with reduced overall survival (HR, 2.440; 95% confidence interval, 1.076-5.530; P=0.033). To conclude, our data demonstrated that Hsp90-β protein was over-expressed in lung ADC tumor tissues and was associated with poor outcomes in early stage ADC patients and low pathological grade tumors. These data suggest that Hsp90-β could be a clinically useful biomarker for the prognosis of ADC and an effective anticancer target.