Objective: Estrogen receptor expression in lung cancer has been understudied, particularly in light of its potential biologic importance in the epidemic of lung cancer in women. The expression of estrogen receptors was investigated to better understand the possible role of sex hormones in lung cancer.
Methods: A total of 301 patients with surgically resected non-small cell lung cancers of stages I to III were explored. Sections of paraffin-embedded tumor samples were stained with estrogen receptor alpha and estrogen receptor beta antibodies. Tumors with moderate-to-strong nuclear staining in at least 50% of the tumor cells were scored as positive for overexpression.
Results: The overall frequency of overexpression for estrogen receptor beta was 45.8% (138/301). It was detected most frequently in female patients (in 54.3% of 127 tumors vs 39.7% of 174 tumors in men, P = .012). However, there was no estrogen receptor alpha nuclear staining detectable in non-small cell lung cancers. Interestingly, a significant correlation between estrogen receptor beta expression, stage of disease, grade of differentiation, smoking status, vascular invasion, and survival in patients with stage II and III disease was found. By using multivariate analysis of survival among patients with stage II and III disease, estrogen receptor beta overexpression, stage II tumor, well differentiation, nonsmoking status, and lack of vascular invasion were significantly favorable prognostic factors.
Conclusions: The results presented here show for the first time that immunohistochemical expression of estrogen receptor beta can be used as a prognostic indicator in patients with surgically resected stage II and III non-small cell lung cancers. These observations might offer a possibility for hormonal therapy in patients with lung cancer.