Expression of Regulatory Factor X1 Can Predict the Prognosis of Breast Cancer

Breast cancer (BC) is the most common malignancy among women. Identifying novel biomarkers to predict prognosis accurately is important in managing this disease. The regulatory factor X1 () gene is a member of the regulatory factor X gene family. Its protein reportedly downregulates the proto-oncogene , but its role in BC has been unclear. In this study, expression and methylation status of were determined in BC cell lines. We then evaluated mRNA expression levels with regard to clinicopathological factors including postoperative prognosis in 167 patients with BC. Expression of was heterogeneous among cell lines, and we found no DNA methylation at the promoter region. Patients were categorized into groups with high or low expression, based on ratio of mRNA expression in BC and adjacent non-cancerous tissues. The high group was significantly associated with low T factor (P=0.028), earlier disease stage (P=0.015), positive expression of estrogen receptor (P=0.005) and progesterone receptor (P=0.011), negative expression of human epidermal growth factor receptor 2 (P=0.001). The high group experienced more favorable disease-free survival (P=0.007) and overall survival (P=0.013). In multivariate analysis, expression was an independent prognostic factor for disease-free survival. Our findings indicate that may serve as a prognostic marker for BC.