Nuclear up regulation of the BRCA1-associated ubiquitinase BAP1 is associated with tumor aggressiveness in prostate cancers lacking the TMPRSS2:ERG fusion

The cover for issue 67 of Oncotarget features Figure 1, "Examples of (A) negative, (B) weak, (C) moderate and (D) strong BAP1 staining in prostate cancer and (E) BAP1 staining of cancerous (Ea) and normal (Eb) prostate glands in the same TMA spot," by Steurer, et al.

Studies on the expression and prognostic role of BAP1 in prostate cancer are currently lacking.

The research team used a tissue microarray of 17,747 individual prostate cancer samples linked with comprehensive pathological, clinical and molecular data and studied the immunohistochemical expression of BAP1.

Dr. Ronald Simon from the Institute of Pathology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany said, "Prostate cancer (PCa) is the most diagnosed cancer among males in Western societies."

Figure 1: Examples of (A) negative, (B) weak, (C) moderate and (D) strong BAP1 staining in prostate cancer and (E) BAP1 staining of cancerous (Ea) and normal (Eb) prostate glands in the same TMA spot. Spot size is 0.6 mm at 100x (inset 400x) magnification.

Mutation, genomic deletion of its locus at 3p21 or loss of BAP1 expression has been reported from various tumor types such as non-small cell lung cancer, renal cell carcinoma, gallbladder cancer, mesothelioma and uveal melanoma, and has been linked to poor prognosis in most of them.

For example, BAP1 loss or germline mutations have been linked to prolonged survival in malignant pleural mesothelioma, and BAP1 overexpression appears to promote basal type breast cancers and myeloid neoplasms harboring certain ATRX mutations.

Also, a recent meta-analysis of 26 BAP1 expression studies in 10 different cancer types concludes that the prognostic implication of BAP1 alterations depends on the tumor type.

One study reported lack of BAP1 mutations in 45 prostate tumors, but data on BAP1 protein expression or its prognostic significance in this disease are currently lacking.

The Simon Research Team concluded, "In summary, up regulation of BAP1 is associated with adverse features, rapid cell proliferation and poor patient prognosis in PCa. BAP1 expression analysis may have prognostic utility either alone or, more likely, in combination with other biomarkers."

Full text - https://www.oncotarget.com/article/27270/text/

Correspondence to - Ronald Simon - [email protected]

Keywords - BAP1, prostate cancer, prognosis, immunohistochemistry