The prognostic role of progesterone receptor expression in non-small cell lung cancer patients: Gender-related impacts and correlation with disease-specific survival

Purpose: Progesterone has been shown to impact the development of hormone-sensitive cancers, such as breast and ovarian cancers. Emerging evidence has revealed a possible role of progesterone in the tumorigenesis of other cancers, including lung cancer. Herein, we aimed to elucidate the prevalence and prognostic significance of progesterone receptor (PR) expression in non-small cell lung cancer (NSCLC) tissue. Experimental: Tumor tissue samples were collected from our patient cohort consisting of 335 NSCLC patients with stage I-IIIA disease. Tissue microarrays (TMAs) were constructed, and immunohistochemical (IHC) analyses were performed to evaluate the PR expression in the tumor epithelial and stromal compartments. Results: In a univariate analysis, positive PR expression in the stromal tumor compartment (P = 0.005) was significantly and independently associated with a favorable outcome for both genders. Furthermore, positive PR expression in tumor epithelial cells (P = 0.003) correlated with a poor prognosis for female patients. In a multivariate analysis, positive PR expression in the tumor stroma (P = 0.007) was an independent prognostic factor for improved disease-specific survival (DSS). Positive PR expression in tumor epithelial cells emerged as an independent prognostic factor in female patients (P = 0.001) for poor DSS. Conclusions: We show that PR expression in tumor-surrounding stromal cells is associated with improved DSS for both male and female patients. Additionally, we reveal that positive PR expression in tumor epithelial cells is an independent, unfavorable prognosticator for DSS in female patients, making PR expression a potential marker for prognostic stratification in NSCLC. (C) 2015 Elsevier Inc. All rights reserved.