Low PBRM1 identifies tumor progression and poor prognosis in breast cancer.

BACKGROUND To investigate the expression and role of PBRM1 in breast cancer, and to evaluate the clinical and prognostic significance of PBRM1 protein in patients with breast cancer. METHODS The expression of PBRM1 was examined in breast cancer tissue and paired non-cancerous tissues by real-time PCR. Moreover, PBRM1 protein expression was evaluated by immunohistochemistry in 150 paraffin-embedded breast cancer specimens. The correlation between PBRM1 expression and clinicopathological features were statistically analyzed. RESULTS The status of PBRM1 protein in breast cancer tissues is much lower than that in paracarcinoma tissues. Low PBRM1 expression was positively correlated with tumor stage (P =0.003) and lymph node metastasis (P =0.013). The overall (P =0.003) and recurrent-free survival (P =0.001) of the patients with high PBRM1 expression was significantly lower than the low PBRM1 expression group. Multivariate analysis showed that the expression of PBRM1 was an independent factor of overall survival for the patients with breast cancer (P =0.030). CONCLUSIONS PBRM1 might involve in the development and progression of breast cancer as a tumor suppressor, and thereby may be a valuable prognostic marker for breast cancer patients.