Association of BRCA1 and BRCA2 Mutations With Survival, Chemotherapy Sensitivity, and Gene Mutator Phenotype in Patients With Ovarian Cancer

Department of Obstetrics and Gynaecology, University of Helsinki, Helsinki, Uusimaa, Finland
JAMA The Journal of the American Medical Association (Impact Factor: 35.29). 10/2011; 306(14):1557-65. DOI: 10.1001/jama.2011.1456
Source: PubMed


Attempts to determine the clinical significance of BRCA1/2 mutations in ovarian cancer have produced conflicting results.
To determine the relationships between BRCA1/2 deficiency (ie, mutation and promoter hypermethylation) and overall survival (OS), progression-free survival (PFS), chemotherapy response, and whole-exome mutation rate in ovarian cancer.
Observational study of multidimensional genomics and clinical data on 316 high-grade serous ovarian cancer cases that were made public between 2009 and 2010 via The Cancer Genome Atlas project.
OS and PFS rates (primary outcomes) and chemotherapy response (secondary outcome).
BRCA2 mutations (29 cases) were associated with significantly better OS (adjusted hazard ratio [HR], 0.33; 95% CI, 0.16-0.69; P = .003 and 5-year OS, 61% for BRCA2-mutated vs 25% for BRCA wild-type cases) and PFS (adjusted HR, 0.40; 95% CI, 0.22-0.74; P = .004 and 3-year PFS, 44% for BRCA2-mutated vs 16% for BRCA wild-type cases), whereas neither BRCA1 mutations (37 cases) nor BRCA1 methylation (33 cases) was associated with prognosis. Moreover, BRCA2 mutations were associated with a significantly higher primary chemotherapy sensitivity rate (100% for BRCA2-mutated vs 82% [P = .02] and 80% [P = .05] for BRCA wild-type and BRCA1-mutated cases, respectively) and longer platinum-free duration (median platinum-free duration, 18.0 months for BRCA2-mutated vs 11.7 [P = .02] and 12.5 [P = .04] months for BRCA wild-type and BRCA1-mutated cases, respectively). BRCA2-mutated, but not BRCA1-mutated cases, exhibited a "mutator phenotype" by containing significantly more mutations than BRCA wild-type cases across the whole exome (median mutation number per sample, 84 for BRCA2-mutated vs 52 for BRCA wild-type cases, false discovery rate <0.1).
Among women with high-grade serous ovarian cancer, BRCA2 mutation, but not BRCA1 deficiency, was associated with improved survival, improved chemotherapy response, and genome instability compared with BRCA wild-type.

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Available from: Ken Hess, Jul 22, 2014
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    • "The phenotype of BRCA-deficient ovarian cancers is of enhanced survival [20] [21] [22] [23], largely attributed to a better response to platinum chemotherapy. This phenotype of enhanced survival appears to also extend to ovarian cancers with deficiencies in other homologous recombination genes [24]. "
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    ABSTRACT: Almost exactly twenty years after their discovery, the BRCA1 and BRCA2 genes have become the target of the first "personalized" therapy available for patients with ovarian cancer. In December 2014, a poly(ADP-ribose) polymerase (PARP) inhibitor was granted expedited approved by the United States Food and Drug Administration for use in advanced ovarian cancer patients with germline BRCA1/2 mutations who have received three or more prior lines of chemotherapy. This review article will discuss (1) the BRCA1 and BRCA2 genes within the larger context of homologous recombination deficiency; (2) the advances in our understanding of hereditary cancer risk and the dramatic shifts that have occurred in the genetic testing landscape since the landmark 2013 Supreme Court ruling invalidating patents on BRCA1 and BRCA2 genetic testing; and (3) the clinical trials leading to the approval of olaparib, the first in human PARP inhibitor. Copyright © 2015. Published by Elsevier Inc.
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    • "We then used drug-free survival analysis to evaluate the possibility of promoter methylation of lincRNAs as drug targets. The drug-free interval was defined as from the end of chemotherapeutic drug treatment to the date of progression or recurrence or last contact (censored) (56). XLOC_007617 was a lincRNA that showed positive correlation between its methylation and drug-free survival in UCEC (log-rank P = 0.013; Supplementary Figure S8). "
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    ABSTRACT: Despite growing consensus that long intergenic non-coding ribonucleic acids (lincRNAs) are modulators of cancer, the knowledge about the deoxyribonucleic acid (DNA) methylation patterns of lincRNAs in cancers remains limited. In this study, we constructed DNA methylation profiles for 4629 tumors and 705 normal tissue samples from 20 different types of human cancer by reannotating data of DNA methylation arrays. We found that lincRNAs had different promoter methylation patterns in cancers. We classified 2461 lincRNAs into two categories and three subcategories, according to their promoter methylation patterns in tumors. LincRNAs with resistant methylation patterns in tumors had conserved transcriptional regulation regions and were ubiquitously expressed across normal tissues. By integrating cancer subtype data and patient clinical information, we identified lincRNAs with promoter methylation patterns that were associated with cancer status, subtype or prognosis for several cancers. Network analysis of aberrantly methylated lincRNAs in cancers showed that lincRNAs with aberrant methylation patterns might be involved in cancer development and progression. The methylated and demethylated lincRNAs identified in this study provide novel insights for developing cancer biomarkers and potential therapeutic targets.
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    • "Individuals with inactivating mutations in BRCA2 exhibit a strong predisposition to cancers of the breast, ovary, and other tissues. However, patients with tumors harboring BRCA2 mutations have an improved prognosis following treatment with platinum-containing and other drugs, compared to patients with tumors with intact BRCA2 genes (Maxwell and Domchek, 2012; Yang et al., 2011). In addition, BRCA2 mutation status leads to differences in metastatic frequency in patients (Bayraktar et al., 2013; James et al., 2009). "
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    ABSTRACT: Tumor cells have unstable genomes relative to non-tumor cells. Decreased DNA integrity resulting from tumor cell instability is important in generating favorable therapeutic indices, and intact DNA repair mediates resistance to therapy. Targeting DNA repair to promote the action of anti-cancer agents is therefore an attractive therapeutic strategy. BRCA2 is involved in homologous recombination repair. BRCA2 defects increase cancer risk but, paradoxically, cancer patients with BRCA2 mutations have better survival rates. We queried TCGA data and found that BRCA2 alterations led to increased survival in patients with ovarian and endometrial cancer. We developed a BRCA2-targeting second-generation antisense oligonucleotide (ASO), which sensitized human lung, ovarian, and breast cancer cells to cisplatin by as much as 60%. BRCA2 ASO treatment overcame acquired cisplatin resistance in head and neck cancer cells, but induced minimal cisplatin sensitivity in non-tumor cells. BRCA2 ASO plus cisplatin reduced respiration as an early event preceding cell death, concurrent with increased glucose uptake without a difference in glycolysis. BRCA2 ASO and cisplatin decreased metastatic frequency in vivo by 77%. These results implicate BRCA2 as a regulator of metastatic frequency and cellular metabolic response following cisplatin treatment. BRCA2 ASO, in combination with cisplatin, is a potential therapeutic anti-cancer agent.
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