Bromodomain-containing Protein 4 Is a Favourable Prognostic Factor in Breast Cancer Patients

Aim: To evaluate the association between bromodomain-containing protein 4 (BRD4) expression and clinicopathological factors and prognosis in human breast cancer specimens. Patients and Methods: We used tissue microarrays constructed from samples of patients (n=183) who underwent surgery. We validated the association between BRD4 expression and prognosis in solid tumours, including breast cancer, using The Cancer Genome Atlas (TCGA) database. Results: Immunohistochemical staining showed that BRD4 was widely distributed in breast cancer tissues. BRD4 was strongly expressed in 19.7% of patients but BRD4 staining intensity was not correlated with other clinicopathological factors. Most importantly, patients with a strong BRD4 expression had a significantly longer disease-specific survival than those with a weak BRD4 expression (100.0% vs. 91.3% at 5 years, p=0.027). mRNA expression analysis showed similar results (91.2% vs. 80.2% at 6 years, p=0.047). Conclusion: Strong BRD4 expression was associated with a significantly better prognosis in breast cancer tumours.