To investigate the expression and clinicopathological significance of the oestrogen receptor (ER) in non-small cell lung cancer (NSCLC).

ER expression was examined by immunohistochemical staining of tumour tissue and adjacent normal lung tissue from 67 NSCLC patients. The relationships between ER expression and clinicopathological features were analysed.

A higher percentage of NSCLC tissues (28/67, 41.79%) than adjacent normal lung tissues (10/55, 18.18%) were ER positive. ER expression correlated with tumour differentiation but not with gender, age, tumour histological type, tumour size, lymph node metastasis, or clinical TNM staging. The median survival times of patients with ER-positive (n = 28) and -negative (n = 39) tumours were 36 and 27 months, respectively. The 1-, 3-, and 5-year survival rates were higher for patients with ER-positive tumours than for patients with ER-negative tumours.

ER expression could be a useful prognostic biomarker and therapeutic target for patients with NSCLC.