Prognostic significance of BAG-1 expression in nonsmall cell lung cancer

The purpose of this study was to evaluate the expression of BAG-1 in a cohort of patients with nonsmall cell lung cancer (NSCLC). The intensity and subcellular distribution of BAG-1 expression were correlated with overall survival. Tumor samples were collected from 85 patients diagnosed with NSCLC between 1993-1995 in St. John's, Newfoundland. Expression of BAG-1 was determined by immunohistochemistry using polyclonal anti-BAG-1 antibody. There was significant variation in the immunohistochemical staining patterns of BAG-1, including nonstaining and staining of either the cytoplasm, nucleus or both. Univariate Cox regression analysis showed that those patients whose tumor overexpressed BAG-1 had a significant reduction in the risk of death (hazard ratio = 0.53, p = 0.03). The survival advantage of patients with BAG-1 overexpression tumor was also demonstrated by Kaplan-Meier analysis and log-rank tests (median survival 30.10 months versus 17.04 months, p = 0.05). In addition, multivariate Cox regression analysis showed that patients whose tumor exhibited intense cytoplasmic staining had a further reduction of the risk of death (hazard ratio = 0.42, p = 0.03) and this effect was independent of age, stage and histology. All stages were included in the analysis. Our preliminary data strongly indicate that further investigation is warranted to better define the role of BAG-1 as an independent prognostic factor in NSCLC.