BRCA1-associated protein 1 expression and prognostic role in prostate adenocarcinoma

As prostate cancer (PCa) is the second most commonly diagnosed cancer worldwide, finding novel markers for prognosis is crucial. BRCA1-associated protein 1 (BAP-1), a nuclear-localized deubiquitinating enzyme, has been reported in several human cancers. However, its prognostic role in PCa remains unknown. Herein, we assessed the prognostic and clinicopathologic significance of BAP-1 in PCa.

Seventy surgical specimens from radical prostatectomy cases were examined. Two cores per case were selected for construction of tissue microarrays (TMAs). After the exclusion of two cases because of tissue sparsity, BAP-1 immunohistochemical expression was evaluated in 68 cases of formalin-fixed, paraffin-embedded TMA tissue blocks. The immunohistochemical stain was scored according to proportion of nuclear staining: negative (<10% of tumor cells) or positive (≥10% of tumor cells).

BAP-1 expression was negative in 30 cases (44.1%) and positive in 38 cases (55.9%). Positive BAP-1 expression was more common in pT3b disease than in pT2 (p=0.038). A high preoperative prostate-specific antigen level was correlated with BAP-1 expression (p=0.014). Age, lymphovascular invasion, perineural invasion, and grade group were not significantly correlated with BAP-1 expression. Patients with positive BAP-1 expression showed significantly shorter disease-free survival (p=0.013). Additionally, BAP-1 was an independent prognostic factor of PCa (p=0.035; hazard ratio, 9.277; 95% confidence interval, 1.165-73.892).

Our study findings showed an association of BAP-1 expression with poor PCa prognosis and suggest a potential role for BAP-1 as a prognostic biomarker for PCa.