Routine use of gene panel testing in hereditary breast cancer should be performed with caution

Spectrum of High-Risk Mutations among Breast Cancer Patients Referred for Multigene Panel Testing in a Romanian Population

(1) Background: Multigene panel testing for Hereditary Breast and Ovarian Cancer (HBOC) using next generation sequencing (NGS) is becoming a standard in medical care. There are insufficient genetic studies reported on breast cancer (BC) patients from Romania and most of them are focused only on BRCA 1/2 genes (Breast cancer 1/2). (2) Methods: NGS was performed in 255 consecutive cases of BC referred for management in our clinic between 2015-2019. (3) Results: From the 171 mutations identified, 85 were in the high-penetrance BC susceptibility genes category, 72 were pathogenic genes, and 13 genes were in the (variants of uncertain significance) VUS genes category. Almost half of the mutations were in the BRCA 1 gene. The most frequent BRCA1 variant was c.3607C>T (14 cases), followed by c.5266dupC (11 cases). Regarding BRCA-2 mutations we identified c.9371A>T (nine cases), followed by c.8755-1G>A in three cases, and we diagnosed VUS mutations in three cases. We also identified six pathogenic variants in the PALB2 gene and two pathogenic variants in (tumor protein P 53) TP53. (4) Conclusions: The majority of pathogenic mutations in the Romanian population with BC were in the BRCA 1/ 2 genes, followed by PALB2 (partner and localizer of BRCA2) and TP53, while in the CDH1 (cadherin 1) and STK11 (Serine/Threonine-Protein Kinase) genes we only identified VUS mutations.

The impact of the number of tests presented and a provider recommendation on decisions about genetic testing for cancer risk

OBJECTIVE

To determine how the method of presenting testing options and a provider recommendation can influence a decision about genetic testing for inherited cancer predispositions.

METHODS

An online hypothetical vignette study was completed by 454 healthy volunteers. Participants were randomized to receive one of two survey versions which differed by genetic testing choice presentation. One group was shown three options simultaneously (no test, 5-gene or 15-gene), and a second group received the 15-gene option after choosing between the no test and 5-gene options. A preference-based provider recommendation was also incorporated. We examined the effect of these interventions on test selection.

RESULTS

Participants in the simultaneous group were more likely to choose a genetic test than those in the sequential group (OR: 2.35, p=0.003). This effect was no longer observed when individuals who had selected no-test in the sequential group were told about the 15-gene test (OR: 1.03 p=0.932). Incorporating a provider recommendation into the hypothetical scenario led to more preference-consistent choices (χ2 = 8.53, p < 0.0035,).

CONCLUSIONS

A larger menu of testing choices led to higher testing uptake. A preference-based clinician recommendation resulted in more preference-consistent choices.

PRACTICE IMPLICATIONS

The structuring of testing options and preference-sensitive recommendations appear to facilitate informed testing decisions.

Diagnostic yield of a custom-designed multi-gene cancer panel in Irish patients with breast cancer

BACKGROUND

Breast cancer is genetically heterogeneous, and parellel multi-gene sequencing is the most cost- and time-efficient manner to investigate breast cancer predisposition. Numerous multi-gene panels (MGPs) are commercially available, but many include genes with weak/unproven associaton with breast cancer, or with predisposition to cancer of other types. This study investigates the utility of a custom-designed multi-gene panel in an Irish cohort with breast cancer.

METHODS

A custom panel comprising 83 genes offered by 19 clinical "breast cancer predisposition" MGPs was designed and applied to germline DNA from 91 patients with breast cancer and 77 unaffected ethnicially matched controls. Variants were identified and classified using a custom pipeline.

RESULTS

Nineteen loss-of-function (LOF) and 334 missense variants were identified. After removing common and/or benign variants, 15 LOF and 30 missense variants were analysed. Variants in known breast cancer susceptibility genes were identified, including in BRCA1 and ATM in cases, and in NF1 and CHEK2 in controls. Most variants identified were in genes associated with predisposition to cancers other than breast cancer (BRIP1, RAD50, MUTYH, and mismatch repair genes), or in genes with unknown or unproven association with cancer.

CONCLUSION

Using multi-gene panels enables rapid, cost-effective identification of individuals with high-risk cancer predisposition syndromes. However, this approach also leads to an increased amount of uncertain results. Clinical management of individuals with particular genetic variants in the absence of a matching phenotype/family history is challenging. Further population and functional evidence is required to fully elucidate the clinical relevance of variants in genes of uncertain significance.

Genomic profiling in oncology clinical practice

The development of high-throughput technologies such as next-generation sequencing for DNA sequencing together with the decrease in their cost has led to the progressive introduction of genomic profiling in our daily practice in oncology. Nowadays, genomic profiling is part of genetic counseling, cancer diagnosis, molecular characterization, and as a biomarker of prognosis and response to treatment. Furthermore, germline or somatic genomic characterization of the tumor may provide new treatment opportunities for patients with cancer. In this review, we will summarize the clinical applications and limitations of genomic profiling in oncology clinical practice, focusing on next-generation sequencing.

Multi gene panel testing for hereditary breast cancer - is it ready to be used?

Breast cancer is one of the most common malignancies and the leading cause of death among women worldwide. About 20% of breast cancers are hereditary. Approximately 30% of the mutations have remained negative after testing BRCA1/2 even in families with a Mendelian inheritance pattern for breast cancer. Additional non-BRCA genes have been identified as predisposing for breast cancer. Multi gene panel testing tries to cover and explain the BRCA negative inherited breast cancer, improving efficiency, speed and costs of the breast cancer screening. We identified 23 studies reporting results from individuals who have undergone multi gene panel testing for hereditary breast cancer and noticed a prevalence of 1-12% of non-BRCA genes, but also a high level of variants of uncertain significance. A result with a high level of variants of uncertain significance is likely to be more costly than bring benefits, as well as increase the anxiety for patients. Regarding further development of multi gene panel testing, more research is required to establish both the optimal care of patients with cancer (specific treatments like PARP inhibitors) and the management of unaffected individuals (chemoprevention and/or prophylactic surgeries). Early detection in these patients as well as prophylactic measures will significantly increase the chance of survival. Therefore, multi gene panel testing is not yet ready to be used outside clear guidelines. In conclusion, studies on additional cohorts will be needed to better define the real prevalence, penetrance and the variants of these genes, as well as to describe clear evidence-based guidelines for these patients.

Horizon Scan Of Clinical Laboratories Offering Pharmacogenetic Testing

Pharmacogenetic (PGx) testing involves the analysis of genes known to affect response to medications. The field has been projected as a leading application of personalized or precision medicine, but the use of PGx tests has been stymied, in part, by the lack of clinical evidence of utility and reported low provider awareness. Another factor is the availability of testing. The range and types of PGx tests available have not been assessed to date. In the period September 2017-January 2018 we analyzed the numbers and types of PGx tests offered by clinical testing laboratories in the US. Of the 111 such labs that we identified, we confirmed that 76 offered PGx testing services. Of these, 31 offered only tests for single genes; 30 offered only tests for multiple genes; and 15 offered both types of tests. Collectively, 45 laboratories offered 114 multigene panel tests covering 295 genes. The majority of these tests did not have any clinical guidelines. PGx tests vary in type and makeup, which presents challenges in appropriate test evaluation and selection for providers, insurers, health systems, and patients alike.

Trans-activation-based risk assessment of BRCA1 BRCT variants with unknown clinical significance

Background

Deleterious variants in the tumour suppressor BRCA1 are known to cause hereditary breast and ovarian cancer syndrome (HBOC). Missense variants in BRCA1 pose a challenge in clinical care, as their effect on protein functionality often remains unknown. Many of the pathogenic missense variants found in BRCA1 are located in the BRCA1 C-terminal (BRCT) domains, domains that are known to be vital for key functions such as homologous recombination repair, protein-protein interactions and trans-activation (TA). We investigated the TA activity of 12 BRCA1 variants of unknown clinical significance (VUSs) located in the BRCT domains to aid in the classification of these variants.

Results

Twelve BRCA1 VUSs were investigated using a modified version of the dual luciferase TA activity assay (TA assay) that yielded increased sensitivity and sample throughput. Variants were classified according to American College of Medical Genetics and Genomics (ACMG) criteria using TA assay results and available data. In combining our TA-assay results and available data, in accordance with the ACMG guidelines for variant classification, we proposed the following variant classifications: c.5100A>G, c.5326C>T, c.5348T>C and c.5477A>T as likely benign (class 2) variants. c.5075A>C, c.5116G>A and c.5513T>G were likely pathogenic (class 4), whereas c.5096G>A likely represents a likely pathogenic variant with moderate penetrance. Variants c.5123C>T, c.5125G>A, c.5131A>C and c.5504G>A remained classified as VUSs (class 3).

Conclusions

The modified TA assay provides efficient risk assessment of rare missense variants found in the BRCA1 BRCT-domains. We also report that increased post-transfection incubation time yielded a significant increase in TA assay sensitivity.

Electronic supplementary material

The online version of this article (10.1186/s40246-018-0183-1) contains supplementary material, which is available to authorized users.

Current review of TP53 pathogenic germline variants in breast cancer patients outside Li-Fraumeni syndrome

Pathogenic germline variants in TP53 predispose carriers to the multi-cancer Li-Fraumeni syndrome (LFS). Widespread multigene panel testing is identifying TP53 pathogenic variants in breast cancer patients outside the strict clinical criteria recommended for LFS testing. We aimed to assess frequency and clinical implications of TP53 pathogenic variants in breast cancer cohorts ascertained outside LFS. Classification of TP53 germline variants reported in 59 breast cancer studies, and publicly available population control sets was reviewed and identified evidence for misclassification of variants. TP53 pathogenic variant frequency was determined for: breast cancer studies grouped by ascertainment characteristics; breast cancer cohorts undergoing panel testing; and population controls. Early age of breast cancer onset, regardless of family history or BRCA1/BRCA2 previous testing, had the highest pick-up rate for TP53 carriers. Patients at risk of hereditary breast cancer unselected for features of LFS carried TP53 pathogenic variants at a frequency comparable to that of other non-BRCA1/2 breast cancer predisposing genes, and ∼threefold more than reported in population controls. These results have implications for the implementation of TP53 testing in broader clinical settings, and suggest urgent need to investigate cancer risks associated with TP53 pathogenic variants in individuals outside the LFS spectrum.

Predictors of next-generation sequencing panel selection using a shared decision-making approach

The introduction of next-generation sequencing panels has transformed the approach for genetic testing in cancer patients, however, established guidelines for their use are lacking. A shared decision-making approach has been adopted by our service, where patients play an active role in panel selection and we sought to identify factors associated with panel selection and report testing outcomes. Demographic and clinical data were gathered for female breast and/or ovarian cancer patients aged 21 and over who underwent panel testing. Panel type was classified as ‘breast cancer panel’ (BCP) or ‘multi-cancer panel’ (MCP). Stepwise multiple logistic regression analysis was used to identify clinical factors most predictive of panel selection. Of the 265 included subjects, the vast majority selected a broader MCP (81.5%). Subjects who chose MCPs were significantly more likely to be ≥50 years of age (49 vs. 31%; p < 0.05), Chinese (76 vs. 47%; p < 0.001) and have a personal history of ovarian cancer (41 vs. 8%; p < 0.001) with the latter two identified as the best predictors of panel selection. Family history of cancer was not significantly associated with panel selection. There were no statistically significant differences in result outcomes between the two groups. In summary, our findings demonstrate that the majority of patients have a preference for interrogating a larger number of genes beyond those with established testing guidelines, despite the additional likelihood of uncertainty. Individual factors, including cancer history and ethnicity, are the best predictors of panel selection.

Thanks to next-generation sequencing (NGS) it is possible to test multiple genes for cancer susceptibility quickly and cheaply. At the National Cancer Centre Singapore, shared decision-making is used to actively encourage the involvement of patients in the selection of either a ‘breast cancer panel’ (BCP) or a broader ‘multi-cancer panel’ (MCP) test. Joanne Ngeow at the Centre’s Cancer Genetics Service and colleagues examined the choices made by 265 patients with breast and/or ovarian cancer following detailed pre-test counselling by the genetics team. The majority of patients selected the MCP, potentially highlighting a willingness to accept the additional uncertainty that comes with broader NGS panels. Interestingly, a personal history of ovarian cancer and Chinese ethnicity, but not a family history of cancer, were significantly associated with panel selection.

Non-BRCA1/2 Breast Cancer Susceptibility Genes: A New Frontier with Clinical Consequences for Plastic Surgeons

Twenty percent of breast cancer cases may be related to a genetic mutation conferring an increased risk of malignancy. The most common and prominent breast cancer susceptibility genes are BRCA1 and BRCA2, found in nearly 40% of such cases. However, continued interest and investigation of cancer genetics has led to the identification of a myriad of different breast cancer susceptibility genes. Additional genes, each with unique significance and associated characteristics, continue to be recognized. Concurrently, advanced genetic testing, while still controversial, has become more accessible and cost-effective. As oncologic and reconstructive advances continue to be made in prophylactic breast reconstructive surgery, patients may present to plastic surgeons with an increasingly more diverse array of genetic diagnoses to discuss breast reconstruction. It is therefore imperative that plastic surgeons be familiar with these breast cancer susceptibility genes and their clinical implications. We, therefore, aim to review the most common non-BRCA1/2 breast cancer susceptibility genetic mutations in an effort to assist plastic surgeons in counseling and managing this unique patient population. Included in this review are syndromic breast cancer susceptibility genes such as TP53, PTEN, CDH1, and STK11, among others. Nonsyndromic breast cancer susceptibility genes herein reviewed include PALB2, CHEK2, and ataxia telangiectasia mutated gene. With this knowledge, plastic surgeons can play a central role in the diagnosis and comprehensive treatment, including successful breast reconstruction, of all patients carrying genetic mutations conferring increased risk for breast malignancies.

Genetic Testing: Challenges and Changes in Testing for Hereditary Cancer Syndromes

BACKGROUND

The practice of genetic testing for hereditary cancer syndromes has changed dramatically in recent years, and patients often approach oncology nurses requesting information about genetic testing.
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OBJECTIVES

This article aims to explore changes in cancer genetics, the role of genetics professionals in providing comprehensive genetic care, and the implications of these new developments in genetics for oncology nurses.
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METHODS

A literature review was conducted and focused on articles about the updating of genetic tests with panel testing, insurance changes, alternative genetic counseling strategies, and direct-to-consumer genetic testing.
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FINDINGS

Oncology nurses play an important role in identifying and referring patients, including those who have tested negative for hereditary susceptibility genes, to genetics professionals. Genetics professionals can assist with insurance issues, interpretation of test results, clarification when a variant of unknown clinical significance is detected, and recommendations for care based on personal and family history and testing results. Oncology nurses can assist families with understanding the limitations of direct-to-consumer genetic testing.

Precision reproductive medicine: multigene panel testing for infertility risk assessment

The concept of precision medicine relies on a thorough understanding of the consequences of unique features of individual patients, such as environmental exposures and genetic profiles. A key component of implementing individualized care in this paradigm will be improved assessment of genetic risk. Compared with single gene tests, multigene panel testing-which has recently become commercially available for female infertility-offers the possibility of a more comprehensive and efficient risk evaluation. However, as the use of multigene panel testing for breast cancer risk has shown, this approach must be used judiciously to ensure its usefulness in a clinical setting. Key challenges which have been encountered in oncology include the interpretation of gene variants of questionable clinical effect and a lack of evidence to guide management after variants are identified. In this review, the core concepts of multigene panel testing for risk assessment are discussed, with careful attention to both its shortcomings as well as its potential for benefit in reproductive medicine.