Frequencies of BRCA1 and BRCA2 mutations among 1,342 unselected patients with invasive ovarian cancer
ABSTRACT The heritable fraction of ovarian cancer exceeds that of any other common adult cancer. Most inherited cases of ovarian cancer are due to a germline mutation in BRCA1 or BRCA2. It is important to have an accurate estimate of the proportion of ovarian cancer patients who carry a mutation and the specific factors which predict the presence of a mutation.
We tested a population-based series of 1342 unselected patients diagnosed with invasive ovarian cancer between 1995-1999 and 2002-2004 in Ontario, Canada, for germline mutations in BRCA1 and BRCA2. The two genes were tested in their entirety, using a range of techniques, including multiplex ligation-dependent probe amplification (MLPA).
Among the 1342 women, 176 women carried a mutation (107 in BRCA1, 67 in BRCA2, and two in both genes) for a combined mutation frequency of 13.3%. Seven deletions were identified using MLPA (3.9% of all detected mutations). The prevalence of mutations was particularly high among women diagnosed in their forties (24.0%), in women with serous ovarian cancer (18.0%) and women of Italian (43.5%), Jewish (30.0%) or Indo-Pakistani origin (29.4%). A mutation was seen in 33.9% of women with a first-degree relative with breast or ovarian cancer and in 7.9% of women with no first-degree relative with breast or ovarian cancer. No mutation was seen in women with mucinous carcinoma.
BRCA1 and BRCA2 mutations are common in women with invasive ovarian cancer. All women diagnosed with invasive non-mucinous ovarian cancer should be considered to be candidates for genetic testing.
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ABSTRACT: Background Germline DNA mutations that increase the susceptibility of a patient to certain cancers have been identified in various genes, and patients can be screened for mutations in these genes to assess their level of risk for developing cancer. Traditional methods using Sanger sequencing focus on small groups of genes and therefore are unable to screen for numerous genes from several patients simultaneously. The goal of the present study was to validate a 25-gene panel to assess genetic risk for cancer in 8 different tissues using next generation sequencing (NGS) techniques. Methods Twenty-five genes associated with hereditary cancer syndromes were selected for development of a panel to screen for risk of these cancers using NGS. In an initial technical assessment, NGS results for BRCA1 and BRCA2 were compared with Sanger sequencing in 1864 anonymized DNA samples from patients who had undergone previous clinical testing. Next, the entire gene panel was validated using parallel NGS and Sanger sequencing in 100 anonymized DNA samples. Large rearrangement analysis was validated using NGS, microarray comparative genomic hybridization (CGH), and multiplex ligation-dependent probe amplification analyses (MLPA). Results NGS identified 15,877 sequence variants, while Sanger sequencing identified 15,878 in the BRCA1 and BRCA2 comparison study of the same regions. Based on these results, the NGS process was refined prior to the validation of the full gene panel. In the validation study, NGS and Sanger sequencing were 100% concordant for the 3,923 collective variants across all genes for an analytical sensitivity of the NGS assay of >99.92% (lower limit of 95% confidence interval). NGS, microarray CGH and MLPA correctly identified all expected positive and negative large rearrangement results for the 25-gene panel. Conclusion This study provides a thorough validation of the 25-gene NGS panel and indicates that this analysis tool can be used to collect clinically significant information related to risk of developing hereditary cancers.BMC Cancer 04/2015; 15. DOI:10.1186/s12885-015-1224-y · 3.32 Impact Factor
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ABSTRACT: ABSTRACT Olaparib (Lynparza™; AZD2281) is a potent PARP-1 and PARP-2 inhibitor with biologic activity in ovarian cancer as well as other solid tumors. It has been tested in Phase I and II trials and has single-agent activity in both germline BRCA mutated and sporadic ovarian cancer. Phase III trials assessing the efficacy of olaparib in the maintenance setting following first line and platinum-sensitive recurrence are underway for patients with a germline BRCA mutation, given the inherent molecular compatibility with the drug's mechanism of action.Future Oncology 03/2015; 11(5):747-57. DOI:10.2217/fon.14.313 · 2.61 Impact Factor
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ABSTRACT: Technological advances in DNA sequencing have made gene testing fast and affordable, but there are challenges to the translation of these improvements for patient benefit. The Mainstreaming Cancer Genetics (MCG) programme is exploiting advances in DNA sequencing to develop the infrastructure, processes and capabilities required for cancer gene testing to become routinely available to all those that can benefit. The MCG programme held a consultation day to discuss the development of cancer genetics with senior representation from all 24 UK cancer genetic centres. The current service landscape and capacity for expansion was assessed through structured questionnaires. Workshop discussion addressed the opportunities and challenges to increasing cancer gene testing in the National Health Service (NHS). Services vary with respect to population served and models of service delivery, and with respect to methods and thresholds for determining risk and testing eligibility. Almost all centres want to offer more cancer gene testing (82%) and reported increasing demand for testing from non-genetic clinical colleagues (92%). Reported challenges to increasing testing include the complexity of interpreting the resulting genetic data (79%), the level of funding and complexity of commissioning (67%), the limited capacity of current processes and cross-disciplinary relationships (38%), and workforce education (29%). Priorities to address include the development and evaluation of models of increasing access to gene testing, the optimal process for interpretation of large-scale genetic data, implementation of appropriate commissioning and funding processes, and achieving national consistency. The UK cancer genetics community have high expertise and strong commitment to maximising scientific advances for improved patient benefit and should be pivotally involved in the implementation of increased cancer gene testing.Genome Medicine 02/2015; 7(1):18. DOI:10.1186/s13073-015-0128-4 · 4.94 Impact Factor