Differential role of estrogen receptor beta in early versus metastatic non-small cell lung cancer

Abstract

Although women have an increased susceptibility to lung cancer, they also have a favorable clinical outcome. This may in part be due to female specific genetic and hormonal factors. In the present study, expression of ER-beta was investigated by immunohistochemistry using tissue samples from two cohorts: non-small cell lung cancer (NSCLC) diagnosed in 1999 in Manitoba and advanced NSCLC patients from the NCIC-CTG BR. 18 trial. In the Manitoba cohort assessable tissue samples available in 79 patients (32 females and 47 males) and the majority (75%) had early stage disease. Fifty-one percent of patients expressed high levels of ER-beta (defined by ≥60, the median immunohistochemistry score) and its expression was comparable in males and females. The 3-year overall survival of the group was 53% and males had significantly worse survival compared to females (HR = 2. 37, 95%CI 1. 15-4. 91, P = 0. 02). Higher ER-beta 1 expression was associated with better survival in both univariate (HR = 0. 41, 95%CI 0. 21-0. 80, P = 0. 009) and in multivariate (HR = 0. 37, 95%CI 0. 18-0. 77, P = 0. 008) analysis. In the NCIC-CTG cohort that were more often later stage, assessable tissue samples from 48 cases were available however higher ER-beta 1 expression correlated with poorer survival (HR = 1. 94, 95%CI 1. 01-3. 75 P = 0. 047). These results suggest a differential impact of ER-beta 1 expression on clinical outcome by disease stage, that needs to be explored further and may explain contradictory observations reported in the literature. © 2012 Springer Science+Business Media, LLC.