Reliability of Tumor Testing Compared to Germline Testing for Detecting BRCA1 and BRCA2 Mutations in Patients with Epithelial Ovarian Cancer

BRCA genetic testing and counseling in breast cancer: how do we meet our patients' needs?

BRCA1 and BRCA2 are tumor suppressor genes that have been linked to inherited susceptibility of breast cancer. Germline BRCA1/2 pathogenic or likely pathogenic variants (gBRCAm) are clinically relevant for treatment selection in breast cancer because they confer sensitivity to poly(ADP-ribose) polymerase (PARP) inhibitors. BRCA1/2 mutation status may also impact decisions on other systemic therapies, risk-reducing measures, and choice of surgery. Consequently, demand for gBRCAm testing has increased. Several barriers to genetic testing exist, including limited access to testing facilities, trained counselors, and psychosocial support, as well as the financial burden of testing. Here, we describe current implications of gBRCAm testing for patients with breast cancer, summarize current approaches to gBRCAm testing, provide potential solutions to support wider adoption of mainstreaming testing practices, and consider future directions of testing.

Family Matters: Germline Testing in Thoracic Cancers

Most thoracic cancers arise via a series of stepwise somatic alterations driven by a well-defined carcinogen (ie, tobacco or asbestos for lung cancer and mesothelioma, respectively). A small proportion can emerge on a background of pathogenic germline variants (PGVs), which have the property of heritability. In general, PGVs may be initially suspected on the basis of the presence of specific clinical features. Such gene × environment interactions significantly increase the risk of developing lung cancer (1.5- to 3.2-fold). PGVs have been discovered involving the actionable driver oncogene, epidermal growth factor receptor (EGFR), with an EGFR T790M PGV rate of 0.3%-0.9% in the nonsquamous non-small-cell lung cancer subtype. Its appearance during routine somatic DNA sequencing in those patients who have not had a previous tyrosine kinase inhibitor should raise suspicion. In patients with sporadic mesothelioma, BAP1 is the most frequently mutated tumor driver, with a PGV rate between 2.8% and 8%, associated with a favorable prognosis. BAP1 PGVs accelerate mesothelioma tumorigenesis after asbestos exposure in preclinical models and may be partly predicted by clinical criteria. At present, routine germline genetic testing for thoracic cancers is not a standard practice. Expert genetic counseling is, therefore, required for patients who carry a PGV. Ongoing studies aim to better understand the natural history of patients harboring PGVs to underpin future cancer prevention, precise counseling, and cancer management with the goal of improving the quality and length of life.

The expression and mutation of BRCA1/2 genes in ovarian cancer: a global systematic study

INTRODUCTION

This systematic review was designed to summarize the findings on expression and mutation of BRCA1/2 genes in ovarian cancer (OC) patients, focusing on mutation detection technology and taking clinical decisions for better treatment.

AREAS COVERED

We conducted a systematic review by following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses document selection guidelines for the document selection process and the PICOT standard for developing the keywords to search for. A total of 5729 publications were included, and 50 articles were put into the final screening. The results showed that Next-Generation Sequencing was a breakthrough technology in detecting Breast Cancer 1/2 (BRCA1/2) gene mutations because of its efficacy and affordability. Other technologies are also being applied now for mutation detection. The most prominent associations of BRCA1/2 gene mutations were age, heredity, and family history. Furthermore, mutations of BRCA1/2 could improve survival rate and overall survival. There is no sufficient study available to conclude a systematic analysis for the expression of BRCA1/2 gene in OC.

EXPERT OPINION

Research will continue to develop more diagnostic techniques based on the expression and mutation of BCRA1/2 genes for OC in the near future.

Laboratory Cross-Comparison and Ring Test Trial for Tumor BRCA Testing in a Multicenter Epithelial Ovarian Cancer Series: The BORNEO GEICO 60-0 Study

Germline and tumor BRCA testing constitutes a valuable tool for clinical decision-making in the management of epithelial ovarian cancer (EOC) patients. Tissue testing is able to identify both germline (g) and somatic (s) BRCA variants, but tissue preservation methods and the widespread implementation of NGS represent pre-analytical and analytical challenges that need to be managed. This study was carried out on a multicenter prospective GEICO cohort of EOC patients with known gBRCA status in order to determine the inter-laboratory reproducibility of tissue sBRCA testing. The study consisted of two independent experimental approaches, a bilateral comparison between two reference laboratories (RLs) testing 82 formalin-paraffin-embedded (FFPE) EOC samples each, and a Ring Test Trial (RTT) with five participating clinical laboratories (CLs) evaluating the performance of tissue BRCA testing in a total of nine samples. Importantly, labs employed their own locally adopted next-generation sequencing (NGS) analytical approach. BRCA mutation frequency in the RL sub-study cohort was 23.17%: 12 (63.1%) germline and 6 (31.6%) somatic. Concordance between the two RLs with respect to BRCA status was 84.2% (gBRCA 100%). The RTT study distributed a total of nine samples (three commercial synthetic human FFPE references, three FFPE, and three OC DNA) among five CLs. The median concordance detection rate among them was 64.7% (range: 35.3-70.6%). Analytical discrepancies were mainly due to the minimum variant allele frequency thresholds, bioinformatic pipeline filters, and downstream variant interpretation, some of them with consequences of clinical relevance. Our study demonstrates a wide range of concordance in the identification and interpretation of BRCA sequencing data, highlighting the relevance of establishing standard criteria for detecting, interpreting, and reporting BRCA variants.

Temporal Patterns and Adoption of Germline and Somatic BRCA Testing in Ovarian Cancer

OBJECTIVE

To describe the testing rate, patient characteristics, temporal trends, timing, and results of germline and somatic BRCA testing in patients with ovarian cancer using real-world data.

METHODS

We included a cross-sectional subset of adult patients diagnosed with ovarian cancer between January 1, 2011, and November 30, 2018, who received frontline treatment and were followed for at least 1 year in a real-world database. The primary outcome was receipt of BRCA testing, classified by biosample source as germline (blood or saliva) or somatic (tissue). Lines of therapy (frontline, second line, third line) were derived based on dates of surgery and chemotherapy. Descriptive statistics were analyzed.

RESULTS

Among 2,557 patients, 72.2% (n=1,846) had at least one documented BRCA test. Among tested patients, 62.5% (n=1,154) had only germline testing, 10.6% (n=197) had only somatic testing, and 19.9% (n=368) had both. Most patients had testing before (9.7%, n=276) or during (48.6%, n=1,521) frontline therapy, with 17.6% (n=273) tested during second-line and 12.7% (n=129) tested during third-line therapy. Patients who received BRCA testing, compared with patients without testing, were younger (mean age 63 years vs 66 years, P <.001) and were more likely to be treated at an academic practice (10.4% vs 7.0%, P =.01), with differences by Eastern Cooperative Oncology Group performance score ( P <.001), stage of disease ( P <.001), histology ( P <.001), geography ( P <.001), and type of frontline therapy ( P <.001), but no differences based on race or ethnicity. The proportion of patients who received BRCA testing within 1 year of diagnosis increased from 24.6% of patients in 2011 to 75.6% of patients in 2018.

CONCLUSION

In a large cohort of patients with ovarian cancer, significant practice disparities existed in testing for actionable BRCA mutations. Despite increased testing over time, many patients did not receive testing, suggesting missed opportunities to identify patients appropriate for targeted therapy and genetic counseling.

Corrected Allele Frequency of BRCA1/2 Mutations Is an Independent Prognostic Factor for Treatment Response to PARP-Inhibitors in Ovarian Cancer Patients

PARP inhibitors (PARPi) have increased treatment options in ovarian cancer, particularly in patients with BRCA1/2 mutations, although there are still marked differences in the duration of patients’ response to this targeted therapy. BRCA testing is routinely performed in tumor tissue of ovarian cancer patients. The resulting molecular pathological findings include the genetic nomenclature of the mutation, the frequency of the mutated allele (variant allele frequency, VAF), and the tumor cell content. VAF measures the percentage of mutated alleles from the total alleles in the cells of the examined tissue. The aim of this study was to investigate the significance of VAF on the therapeutic response to PARPis in ovarian cancer patients. Epithelial ovarian cancer patients harboring BRCA1/2 tumor mutations, who underwent germline testing and received PARPi therapy at the Medical University of Vienna (n = 41) were included in the study. Corrected VAF (cVAF) was calculated based on VAF, tumor cell content, and germline mutation. Patients were divided into two groups based on their cVAF. Median PFS under PARPi in patients with low cVAF was 13.0 months (IQR [10.3-not reached]) and was not reached in the high cVAF group. High cVAF was significantly associated with longer PFS in the multivariate analysis (HR = 0.07; 95% CI [0.01–0.63]; p = 0.017). In conclusion, high cVAF was associated with a significantly better response to PARPi in this study population.

Cost Study of the PlasmaJet Surgical Device Versus Conventional Cytoreductive Surgery in Patients With Advanced-Stage Ovarian Cancer

PURPOSE

Adjuvant use of Neutral Argon Plasma (PlasmaJet Surgical Device) during cytoreductive surgery (CRS) for advanced-stage epithelial ovarian cancer improves surgical outcomes. The aim of this study is to examine the costs of adjuvant use of the PlasmaJet during surgery compared with conventional CRS in advanced-stage epithelial ovarian cancer.

MATERIALS AND METHODS

The patients were randomly assigned to surgery with or without the PlasmaJet. Analysis of the intra- and extramural health care costs was performed. Costs were divided into three categories: costs of the diagnostic phase (T1), inpatient care up to discharge including costs of surgery (T2), and outpatient care including chemotherapy until 6 weeks after the last cycle of chemotherapy (T3).

RESULTS

Overall, 327 patients underwent CRS (surgery with PlasmaJet: n = 157; conventional surgery: n = 170). The mean total health costs were significantly higher for CRS with adjuvant use of PlasmaJet compared with conventional CRS (€19,414 v €18,165, P = .017). Costs are divided into costs of the diagnostic phase (€2,034 v €1,974, P = .890), costs of inpatient care (€10,956 v €9,556, P = .003), and costs of outpatient care (€6,417 v €6,628, P = .147).

CONCLUSION

Mean total health care costs of the use of PlasmaJet in CRS were significantly higher than those for conventional CRS. This difference is fully explained by the additional surgery costs of the use of PlasmaJet. However, surgery with the use of the PlasmaJet leads to a significantly higher percentage of complete CRS and a halving of stomas. A cost-effectiveness analysis will be performed once survival data are available (funded by ZonMw, Trial Register NL62035.078.17).

Epithelial Ovarian Cancer: Providing Evidence of Predisposition Genes

Epithelial ovarian cancer (EOC) is one of the cancers most influenced by hereditary factors. A fourth to a fifth of unselected EOC patients carry pathogenic variants (PVs) in a number of genes, the majority of which encode for proteins involved in DNA mismatch repair (MMR) pathways. PVs in BRCA1 and BRCA2 genes are responsible for a substantial fraction of hereditary EOC. In addition, PV genes involved in the MMR pathway account for 10–15% of hereditary EOC. The identification of women with homologous recombination (HR)-deficient EOCs has significant clinical implications, concerning chemotherapy regimen planning and development as well as the use of targeted therapies such as poly(ADP-ribose) polymerase (PARP) inhibitors. With several genes involved, the complexity of genetic testing increases. In this context, next-generation sequencing (NGS) allows testing for multiple genes simultaneously with a rapid turnaround time. In this review, we discuss the EOC risk assessment in the era of NGS.

Real-World Data on Detection of Germline and Somatic Pathogenic/Likely Pathogenic Variants in BRCA1/2 and Other Susceptibility Genes in Ovarian Cancer Patients Using Next Generation Sequencing

Simple Summary

Genotyping of BRCA genes is required for treatment with PARP inhibitors. Purposing to address treatment needs and familial cancer risk, the aim of our study was to introduce the most appropriate testing workflow in epithelial ovarian cancer patients (EOC) using germline and tumor genotyping of BRCA and other hereditary breast and/or ovarian cancer (HBOC) susceptibility genes. In consecutive patients with advanced non-mucinous EOC, who responded to platinum-based chemotherapy, germline and tumor genotyping were performed using Illumina’s next generation sequencing (NGS) panels. Sensitivity of tumor genotyping for detection of germline pathogenic/likely pathogenic variants (PV/LPV) was 96.2% for BRCA and 93.3% for HBOC genes. With germline genotyping-only strategy, 58.8% of HBOC PV/LPV and 68.4% of BRCA PV/LPV were detected. By tumor genotyping-only, 96.1% of HBOC PV/LPV and 97.4% of BRCA PV/LPV were detected. Tumor genotyping first followed by germline genotyping detects nearly all germline and somatic PV/LPV in the shortest time.

Abstract

Detection of germline and somatic pathogenic/likely pathogenic variants (PV/LPV) in BRCA genes is at the moment a prerequisite for use of PARP inhibitors in different treatment settings of different tumors. The aim of our study was to determine the most appropriate testing workflow in epithelial ovarian cancer (EOC) patients using germline and tumor genotyping of BRCA and other hereditary breast and/or ovarian cancer (HBOC) susceptibility genes. Consecutive patients with advanced non-mucinous EOC, who responded to platinum-based chemotherapy, were included in the study. DNA extracted from blood and FFPE tumor tissue were genotyped using NGS panels TruSightCancer/Hereditary and TruSight Tumor 170. Among 170 EOC patients, 21.8% had BRCA germline or somatic PV/LPV, and additionally 6.4% had PV/LPV in other HBOC genes. Sensitivity of tumor genotyping for detection of germline PV/LPV was 96.2% for BRCA genes and 93.3% for HBOC genes. With germline genotyping-only strategy, 58.8% of HBOC PV/LPV and 68.4% of BRCA PV/LPV were detected. By tumor genotyping-only strategy, 96.1% of HBOC PV/LPV and 97.4% of BRCA PV/LPV were detected. Genotyping of tumor first, followed by germline genotyping seems to be a reasonable approach for detection of PV/LPV in breast and/or ovarian cancer susceptibility genes in non-mucinous EOC patients.

Landscape of germline cancer predisposition mutations testing and management in pediatrics: Implications for research and clinical care

As germline genetic testing capacities have improved over the last two decades, increasingly more people are newly diagnosed with germline cancer susceptibility mutations. In the wake of this growth, there remain limitations in both testing strategies and translation of these results into morbidity- and mortality-reducing practices, with pediatric populations remaining especially vulnerable. To face the challenges evoked by an expanding diversity of germline cancer mutations, we can draw upon a model cancer-associated genetic condition for which we have developed a breadth of expertise in managing, Trisomy 21. We can additionally apply advances in other disciplines, such as oncofertility and pharmacogenomics, to enhance care delivery. Herein, we describe the history of germline mutation testing, epidemiology of known germline cancer mutations and their associations with childhood cancer, testing limitations, and future directions for research and clinical care.

Molecular Pathology of Cancer: The Past, the Present, and the Future

Clinical pathology developed from the study of macroscopic organ and tissue changes at autopsies [...].