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- Fiorentino, M., et al.
(författare)
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Immunohistochemical Expression of BRCA1 in Prostate Cancer
- 2009
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Ingår i: Laboratory Investigation. - : Nature Publishing Group. - 0023-6837 .- 1530-0307. ; 22, s. 169A-169A
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Background: BRCA1 is a multifunctional protein involved in DNA repair, gene transcription and the regulation of cell-cycle check-points. While germline mutations of BRCA1 are rare in prostate cancer and seem to play a limited role in tumor susceptibility, BRCA1 expression has not been investigated to date.Design: We analyzed the immunohistochemical expression of BRCA1 in paraffin embedded samples from 524 men with prostate cancer belonging to the Physicians’ Health Study and the Swedish Watchful Waiting cohorts of prostate cancer patients. High density tissue micro-arrays (TMA) including at least three tumor cores for each case were utilized for the immunohistochemical staining with the monoclonal MS110 antibody specific for the N-terminus of the 220 kDa BRCA1 protein. Cases were scored as negative or positive for BRCA1 immunostaining. The Ki67 proliferation index was also assessed on the same TMAs and evaluated by quantitative image analysis.Results: A positive nuclear immunostaining for BRCA1 was revealed in 62 of 524 (11.9%) patients while normal prostate control cores were all negative. BRCA1 positive tumors were associated with 4 times greater proliferation rate compared to BRCA1 negative tumors (p ∼ 0.0003). In addition, we found a linear trend such that tumors with greater number of TMA cores expressing BRCA1 had stronger extent of proliferation. Men with BRCA1 positive tumors had a slightly higher Gleason’s score (mean 7.5) compared to those negative for BRCA1 (mean 7) No significant correlation was found between BRCA1 staining and cancer-specific death.Conclusions: BRCA1 protein is expressed in a small subset of prostate cancers characterized by high proliferation index but not in normal prostate tissue. Expression of BRCA1 might be acquired in selected tumors to prevent DNA damage in actively replicating cells. A different role independent of germline mutations might be disclosed for BRCA1 as cell cycle regulator in prostate cancer.
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| 2. |
- Penney, K. L., et al.
(författare)
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mRNA expression signature of Gleason grade predicts lethal prostate cancer
- 2011
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Ingår i: Journal of Clinical Oncology. - : American Society of Clinical Oncology. - 0732-183X .- 1527-7755. ; 29:17, s. 2391-2396
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: Prostate-specific antigen screening has led to enormous overtreatment of prostate cancer because of the inability to distinguish potentially lethal disease at diagnosis. We reasoned that by identifying an mRNA signature of Gleason grade, the best predictor of prognosis, we could improve prediction of lethal disease among men with moderate Gleason 7 tumors, the most common grade, and the most indeterminate in terms of prognosis.PATIENTS AND METHODS: Using the complementary DNA-mediated annealing, selection, extension, and ligation assay, we measured the mRNA expression of 6,100 genes in prostate tumor tissue in the Swedish Watchful Waiting cohort (n = 358) and Physicians' Health Study (PHS; n = 109). We developed an mRNA signature of Gleason grade comparing individuals with Gleason ≤ 6 to those with Gleason ≥ 8 tumors and applied the model among patients with Gleason 7 to discriminate lethal cases.RESULTS: We built a 157-gene signature using the Swedish data that predicted Gleason with low misclassification (area under the curve [AUC] = 0.91); when this signature was tested in the PHS, the discriminatory ability remained high (AUC = 0.94). In men with Gleason 7 tumors, who were excluded from the model building, the signature significantly improved the prediction of lethal disease beyond knowing whether the Gleason score was 4 + 3 or 3 + 4 (P = .006).CONCLUSION: Our expression signature and the genes identified may improve our understanding of the de-differentiation process of prostate tumors. Additionally, the signature may have clinical applications among men with Gleason 7, by further estimating their risk of lethal prostate cancer and thereby guiding therapy decisions to improve outcomes and reduce overtreatment.
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