Dataset Information

The performance of BRCA1 immunohistochemistry for detecting germline, somatic, and epigenetic BRCA1 loss in high-grade serous ovarian cancer.

ABSTRACT:

Background

BRCA1 expression can be lost by a variety of mechanisms including germline or somatic mutation and promotor hypermethylation. Given the potential importance of BRCA1 loss as a predictive and prognostic biomarker in high-grade serous ovarian cancer, we sought to evaluate the utility of BRCA1 immunohistochemistry (IHC) in screening for BRCA1 loss by germline, somatic, and epigenetic mechanisms.

Patients and methods

Patients with advanced high-grade serous ovarian cancer who had previously undergone germline BRCA1 testing were identified. Samples from each tumor were stained for BRCA1 and reviewed independently by two pathologists blinded to BRCA status. Tumors with abnormal BRCA1 IHC and wild-type germline testing underwent further evaluation for somatic BRCA1 mutations and promoter hypermethylation. McNemar's test was used to determine the association of BRCA1 IHC with germline BRCA1 mutations and BRCA1 loss through any mechanism. Kaplan-Meier methods were used to estimate overall survival (OS), and the log-rank test was used to assess differences between groups.

Results

Inter-rater reliability between the two pathologists on BRCA IHC interpretation was very good (kappa coefficient 0.865, P = 0.16; McNemar's test). BRCA1 IHC was abnormal in 36% (48/135) of cases. When compared with germline BRCA1 status, BRCA1 IHC had a high negative predictive value (95.4%) but a low positive predictive value (PPV, 52.1%). When accounting for promoter hypermethylation and somatic mutations as alternative methods of BRCA1 loss, the PPV rose to 87.5%. Five-year OS rate was 49.6% [95% confidence interval (CI) 26.3% to 69.3%] for patients with germline BRCA1 mutations, 50.4% (95% CI 27.5% to 69.5%) for germline wild-type BRCA1 and abnormal IHC, and 52.1% (95% CI 38.4% to 64.2%) for germline wild-type BRCA1 and normal IHC (P = 0.92).

Conclusions

BRCA1 IHC interpretation was a highly reproducible and accurate modality for detecting germline, somatic, or epigenetic mechanisms of BRCA1 loss. These results support further development of BRCA1 IHC as a potential biomarker for BRCA1 loss in high-grade serous ovarian cancer.

SUBMITTER: Meisel JL

PROVIDER: S-EPMC4271017 | biostudies-literature | 2014 Dec

REPOSITORIES: biostudies-literature

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Publications

The performance of BRCA1 immunohistochemistry for detecting germline, somatic, and epigenetic BRCA1 loss in high-grade serous ovarian cancer.

Meisel J L JL Hyman D M DM Garg K K Zhou Q Q Dao F F Bisogna M M Gao J J Schultz N D ND Grisham R N RN Phillips M M Iasonos A A Kauff N D ND Levine D A DA Soslow R A RA Spriggs D R DR

Annals of oncology : official journal of the European Society for Medical Oncology 20141003 12

<h4>Background</h4>BRCA1 expression can be lost by a variety of mechanisms including germline or somatic mutation and promotor hypermethylation. Given the potential importance of BRCA1 loss as a predictive and prognostic biomarker in high-grade serous ovarian cancer, we sought to evaluate the utility of BRCA1 immunohistochemistry (IHC) in screening for BRCA1 loss by germline, somatic, and epigenetic mechanisms.<h4>Patients and methods</h4>Patients with advanced high-grade serous ovarian cancer w ...[more]

PMID: 25281711

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Project description:BACKGROUND:Poly (ADP-ribose) polymerase inhibitors targeting BRCA1/2 mutations are available for treating patients with high-grade serous ovarian cancer. These treatments may be more appropriately directed to patients who might respond if the tumor tissue is additionally tested by next-generation sequencing with a multi-gene panel and Sanger sequencing of a blood sample. In this study, we compared the results obtained using the next-generation sequencing multi-gene panel to a known germline BRCA1/2 mutational state determined by conventional Sanger sequencing to evaluate the landscape of somatic mutations in high-grade serous ovarian cancer tumors. METHODS:Cancer tissue from 98 patients with high-grade serous ovarian cancer who underwent Sanger sequencing for germline BRCA1/2 analysis were consecutively analyzed for somatic mutations using a next-generation sequencing 170-gene panel. RESULTS:Twenty-four patients (24.5%) showed overall BRCA1/2 mutations. Seven patients (7.1%) contained only somatic BRCA1/2 mutations with wild-type germline BRCA1/2, indicating acquired mutation of BRCA1/2. Three patients (3.1%) showed reversion of germline BRCA1 mutations. Among the 14 patients (14.3%) with both germline and somatic mutations in BRCA1/2, two patients showed different variations of BRCA1/2 mutations. The next-generation sequencing panel test for somatic mutation detected other pathogenic variations including RAD51D and ARID1A, which are possible targets of poly (ADP-ribose) polymerase inhibitors. Compared to conventional Sanger sequencing alone, next-generation sequencing-based tissue analysis increased the number of candidates for poly (ADP-ribose) polymerase inhibitor treatment from 17.3% (17/98) to 26.5% (26/98). CONCLUSIONS:Somatic mutation analysis by next-generation sequencing, in addition to germline BRCA1/2 mutation analysis, should become the standard of care for managing women with high-grade serous ovarian cancer to widen the indication of poly (ADP-ribose) polymerase inhibitors.

Dataset Information

The performance of BRCA1 immunohistochemistry for detecting germline, somatic, and epigenetic BRCA1 loss in high-grade serous ovarian cancer.

Background

Patients and methods

Results

Conclusions

Publications

The performance of BRCA1 immunohistochemistry for detecting germline, somatic, and epigenetic BRCA1 loss in high-grade serous ovarian cancer.

Similar Datasets

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