Germline whole genome sequencing in adults with multiple primary tumors

Multiple primary tumors (MPTs) are a harbinger of hereditary cancer syndromes. Affected individuals often fit genetic testing criteria for a number of hereditary cancer genes and undergo multigene panel testing. Other genomic testing options, such as whole exome (WES) and whole genome sequencing (WGS) are available, but the utility of these genomic approaches as a second-tier test for those with uninformative multigene panel testing has not been explored. Here, we report our germline sequencing results from WGS in 9 patients with MPTs who had non-informative multigene panel testing. Following germline WGS, sequence (agnostic or 735 selected genes) and copy number variant (CNV) analysis was performed according to the American College of Medical Genetics (ACMG) standards and guidelines for interpreting sequence variants and reporting CNVs. In this cohort, WGS, as a second-tier test, did not identify additional pathogenic or likely pathogenic variants in cancer predisposition genes. Although we identified a CHEK2 likely pathogenic variant and a MUTYH pathogenic variant, both were previously identified in the multigene panels and were not explanatory for the presented type of tumors. CNV analysis also failed to identify any pathogenic or likely pathogenic variants in cancer predisposition genes. In summary, after multigene panel testing, WGS did not reveal any additional pathogenic variants in patients with MPTs. Our study, based on a small cohort of patients with MPT, suggests that germline gene panel testing may be sufficient to investigate these cases. Future studies with larger sample sizes may further elucidate the additional utility of WGS in MPTs.

Power of NGS-based tests in HSP diagnosis: analysis of massively parallel sequencing in clinical practice

Hereditary spastic paraplegia (HSP) refers to a group of heterogeneous neurological disorders mainly characterized by corticospinal degeneration (pure forms), but sometimes associated with additional neurological and extrapyramidal features (complex HSP). The advent of next-generation sequencing (NGS) has led to huge improvements in knowledge of HSP genetics and made it possible to clarify the genetic etiology of hundreds of "cold cases," accelerating the process of reaching a molecular diagnosis. The different NGS-based strategies currently employed as first-tier approaches most commonly involve the use of targeted resequencing panels and exome sequencing, whereas genome sequencing remains a second-tier approach because of its high costs. The question of which approach is the best is still widely debated, and many factors affect the choice. Here, we aim to analyze the diagnostic power of different NGS techniques applied in HSP, by reviewing 38 selected studies in which different strategies were applied in different-sized cohorts of patients with genetically uncharacterized HSP.

Multigene germline testing usefulness instead of BRCA1/2 single screening in triple negative breast cancer cases

Triple negative breast cancer is considered as the worst aggressive subtype with poor prognosis. Recent studies suggest a hereditary component is involved in TNBC development, especially in young patients. However, genetic spectrum remains unclear. Our purpose was to evaluate the usefulness of multigene panel testing in triple negative patients compared to overall breast cancer cases as well as contributing to elucidate which genes are most implicated in triple negative subtype development. Two breast cancer cohorts, comprising 100 triple negative breast cancer patients and 100 patients with other breast cancer subtypes, were analyzed by Next-Generation Sequencing using an On-Demand panel which included 35 predisposition cancer genes associated with inherited cancer susceptibility. The percentage of germline pathogenic variant carriers was higher in the triple negative cohort. ATM, PALB2, BRIP1 and TP53 were the most non-BRCA mutated genes. Moreover, triple negative breast cancer patients without family history related who were identified as carriers were diagnosed at significantly earlier age. As conclusion, our study reinforces the usefulness of multigene panel testing in breast cancer cases but specifically in those with triple negative subtype regardless family history.

Occurrence of variants of unknown clinical significance in genetic testing for hereditary breast and ovarian cancer syndrome and Lynch syndrome: a literature review and analytical observational retrospective cohort study

BACKGROUND AND PURPOSE

Over the last decade, the implementation of multigene panels for hereditary tumor syndrome has increased at our institution (Inselspital, University Hospital Berne, Switzerland). The aim of this study was to determine the prevalence of variants of unknown significance (VUS) in patients with suspected Lynch syndrome and suspected hereditary breast and ovarian cancer syndrome, the latter in connection with the trend toward ordering larger gene panels.

RESULTS

Retrospectively collected data from 1057 patients at our institution showed at least one VUS in 126 different cases (11.9%). In patients undergoing genetic testing for BRCA1/2, the prevalence of VUS was 6%. When < 10 additional genes were tested in addition to BRCA1/2, the prevalence increased to 13.8%, and 31.8% for > 10 additional genes, respectively. The gene most frequently affected with a VUS was ATM. 6% of our patients who were tested for Lynch syndrome had a VUS result in either MLH1, MSH2 or MSH6.

CONCLUSIONS

Our data demonstrate that panel testing statistically significantly increases VUS rates due to variants in non-BRCA genes. Good genetic counseling before and after obtaining results is therefore particularly important when conducting multigene panels to minimize patient uncertainty due to VUS results.

Predictors of Women's Intentions to Communicate Updated Genetic Test Results to Immediate and Extended Family Members

INTRODUCTION

Many individuals who previously received negative genetic test results are eligible for updated testing. This study examined intention to communicate updated genetic test results to relatives in participants who previously received negative genetic test results.

METHODS

Women with a personal or family history of breast or ovarian cancer who tested negative for BRCA1/2 before 2013 were enrolled between April 2018 and October 2019. Proportions were calculated to assess intention to communicate updated genetic test results to living immediate family, extended family, and all family. Potential predictors of intentions from the theory of planned behavior (attitudes, subjective norms, perceived behavioral control) were assessed. The three outcomes were analyzed using generalized linear models with a quasi-binomial probability distribution.

RESULTS

110 women completed the baseline assessment prior to updated testing. Participants intended to communicate genetic test results to 90% of immediate family, 51% of extended family, and 66% of all living relatives. Participants with higher subjective norms (aOR = 1.93, 95% CI: 1.08-3.57) had higher intentions to communicate genetic test results to extended family, while participants with more positive attitudes (aOR = 1.27, 95% CI: 1.01-1.60) had higher intentions to communicate to all family. Placing higher importance on genetic information was associated with higher intentions to communicate to immediate family (aOR = 1.40, 95% CI: 1.06-1.83). Lower subjective numeracy was associated with higher intentions to communicate to extended family (aOR = 0.50, 95% CI: 0.32-0.76).

CONCLUSION

Attitudes and subjective norms were predictors of intention to communicate updated genetic information to at-risk biological relatives, and predictors may vary by degree of relationship.

Identification of hereditary breast and ovarian cancer germline variants in Granada (Spain): NGS perspective

The aim of this study was to assess the prevalence of germline variants in cancer-predisposing genes by either targeted (BRCA1/2) or multigene NGS panel in a high-risk Hereditary Breast and Ovarian Cancer (HBOC) cohort. Samples from 824 Caucasian probands were retrospectively collected and the impact of genetic diagnosis and genetic variants epidemiology in this cohort was evaluated. Performance of risk-reducing prophylactic measures, such as prophylactic mastectomy and/or prophylactic oophorectomy, was assessed through clinical follow-up of patients with a positive genetic result. Pathogenic variants predisposing to HBOC were identified in 11.9% (98/824) individuals at BRCA2 (47/98), BRCA1 (24/98), PALB2 (8/51), ATM (7/51), CHEK2 (6/51) MSH6, (2/51), RAD51C (2/51) and TP53 (2/386). Of them, 11 novel pathogenic variants and 12 VUS were identified, characterized, and submitted to ClinVar. Regarding clinical impact, the risk of developing basal or Her2 breast cancer was increased 15.7 times or 37.5 times for BRCA1 and MSH6 pathogenic variants respectively. On the contrary, the risk of developing basal or luminal A breast cancer was reduced to 81% or 77% for BRCA2 and BRCA1 pathogenic variants, respectively. Finally, 53.2% of individuals testing positive for class IV/V variants underwent prophylactic surgery (mastectomy, oophorectomy or both) being significantly younger at the cancer diagnosis than those undertaking prophylactic measures (p = 0.008). Of them, 8 carried a pathogenic/likely pathogenic variant in other genes different from BRCA1 and BRCA2, and the remaining (46.7%) decided to continue with clinical follow-up. No differences in pathogenicity or risk of developing cancer were found for BRCA1/2 between targeted and multigene sequencing strategies; however, NGS was able to resolve a greater proportion of high-risk patients.

[MUTYH-associated polyposis: Review and update of the French recommendations established in 2012 under the auspices of the National Cancer Institute (INCa)]

MUTYH-associated polyposis (MUTYH-associated polyposis, MAP) is an autosomal recessive inheritance disorder related to bi-allelic constitutional pathogenic variants of the MUTYH gene which was first described in 2002. In 2011, a group of French experts composed of clinicians and biologists, performed a summary of the available data on this condition and drew up recommendations concerning the indications and the modalities of molecular analysis of the MUTYH gene in index cases and their relatives, as well as the management of affected individuals. In view of recent developments, some recommendations have become obsolete, in particular with regard to the molecular analysis strategy since MUTYH gene has been recently included in a consensus panel of 14 genes predisposing to colorectal cancer. This led us to revise all the points of the previous expertise. We report here the revised version of this work which successively considers the phenotype and the tumor risks associated with this genotype, the differential diagnoses, the indication criteria and the strategy of the molecular analysis and the recommendations for the management of affected individuals. We also discuss the phenotype and the tumor risks associated with mono-allelic pathogenic variants of MUTYH gene.

Increased diagnostic yield by reanalysis of data from a hearing loss gene panel

Background

Congenital hearing loss affects approximately 1–2 infants out of every 1000, with 50% of the cases resulting from genetic factors. Targeted gene panels have been widely used for genetic diagnosis of hearing loss. This study aims to reveal new diagnoses via reanalyzing historical data of a multigene panel, and exam the reasons for new diagnoses.

Methods

A total of 210 samples were enlisted, including clinical reports and sequencing data of patients with congenital/prelingual hearing loss who were referred to clinical genetic testing from October 2014 to June 2017. All variants listed on the original clinical reports were reinterpreted according to the standards and guidelines recommended by the American College of Medical Genetics and Genomics and the Association for Molecular Pathology (ACMG/AMP). Expanded analysis of raw data were performed in undiagnosed cases.

Results

Re-analysis resulted in nine new diagnoses, improving the overall diagnostic rate from 39 to 43%. New diagnoses were attributed to newly published clinical evidence in the literature, adoption of new interpretation guidelines and expanded analysis range.

Conclusion

This work demonstrates benefits of reanalysis of targeted gene panel data, indicating that periodical reanalysis should be performed in clinical practice.

Electronic supplementary material

The online version of this article (10.1186/s12920-019-0531-6) contains supplementary material, which is available to authorized users.

Outcomes of retesting BRCA negative patients using multigene panels

The utility of multigene panels in retesting patients who previously tested negative for a pathogenic mutation by BRCA1/2 testing is not well established. Patients who previously tested negative for a pathogenic BRCA1/2 mutation by standard sequencing, and who were seen in cancer genetics center between November 1, 2012 and June 30, 2015 for additional testing utilizing multigene panels, were identified using our genetic testing registry. Data on demographics, personal and family history of cancer, results of panel testing and the impact on patient management was collected retrospectively. A total of 122 patients underwent retesting during the study period. Thirteen (11%) pathogenic mutations were identified in the following genes: CHEK2(4), PALB2(3), ATM(2), CDH1, APC, BARD1 and MRE11A. Eleven out of these thirteen mutations were deemed actionable based on published guidelines. Of these eleven, seven patients had an actual change in clinical management as a result of retesting. Furthermore, retesting also led to a change in clinical management in the two patients with mutations in genes (BARD1 and MRE11A) which do not have clear guidelines for management. There were no significant differences in demographics and personal and family history of cancer between patients who tested positive and those who tested negative on retesting. This study demonstrates the clinical utility of multigene panels in a group of high risk individuals who previously tested negative for a BRCA1/2 mutation. This retesting approach revealed a pathogenic mutation in 11% of cases. Retesting led to significant change in clinical management in a majority of patients with actionable mutations (7 out of 11), as well as in those with mutations in genes which do not have specific management guidelines.

Variants of cancer susceptibility genes in Korean BRCA1/2 mutation-negative patients with high risk for hereditary breast cancer

BACKGROUND

We evaluated the incidence and spectrum of pathogenic and likely pathogenic variants of cancer susceptibility genes in BRCA1/2 mutation-negative Korean patients with a high risk for hereditary breast cancer using a comprehensive multigene panel that included 35 cancer susceptibility genes.

METHODS

Samples from 120 patients who were negative for BRCA1/2 mutations, but had been diagnosed with breast cancer that was likely hereditary, were prospectively evaluated for the prevalence of high-penetrance and moderate-penetrance germline mutations.

RESULTS

Nine patients (7.5%) had at least one pathogenic or likely pathogenic variant. Ten variants were identified in these patients: TP53 in two patients, PALB2 in three patients, BARD1 in two patients, BRIP1 in two patients, and MRE11A in one patient. We also identified 30 types of 139 variants of unknown significance (VUS). High-penetrance germline mutations, including TP53 and PALB2, tended to occur with high frequency in young (< 35 years) breast cancer patients (4/19, 21.1%) than in those diagnosed with breast cancer at ≥35 years of age (1/101, 1.0%; p = 0.003).

CONCLUSIONS

These combined results demonstrate that multigene panels offer an alternative strategy for identifying veiled pathogenic and likely pathogenic mutations in breast cancer susceptibility genes.

The Era of Multigene Panels Comes? The Clinical Utility of Oncotype DX and MammaPrint

The AJCC Cancer Staging Manual, eighth edition published in late 2016, will become the new global guideline for cancer diagnosis and treatment from January 1, 2018. The new edition for the tumor staging system has numerous updates, including building up the prognostic stage group of tumors for the first time and adding a large number of non-anatomical factors into the prognostic evaluation. Oncotype DX and MammaPrint are two of the genomic predictors that will be part of routine clinical practice in the future. Numerous studies have proved the clinical utility of multigene panels in predicting clinical outcome and treatment response. Here we present our review of the studies on these multigene panels and their application to breast cancer.

Identification of mutations in Korean patients with amyotrophic lateral sclerosis using multigene panel testing

Amyotrophic lateral sclerosis (ALS) is a rapidly progressive neurodegenerative disease involving motor neurons. Because a growing number of genes have been identified as the genetic etiology of ALS, simultaneous screening of mutations in multiple genes is likely to be more efficient than gene-by-gene testing. In this study, we performed a multigene panel testing by using targeted capture of 18 ALS-related genes followed by next-generation sequencing. Using this technique, we tried to identify mutations in 4 index patients with familial ALS and 148 sporadic ALS in Korean population and identified 4 known mutations in SOD1, ALS2, MAPT, and SQSTM1 genes, respectively, and 28 variants of uncertain significance in 9 genes. Among the 28 variants of uncertain significance, 6 missense variants were found in highly conserved residues and were consistently predicted to be deleterious by in silico analyses. These results suggest that multigene panel testing is an effective approach for mutation screening in ALS-related genes. Moreover, the relatively low frequency of mutations in known ALS genes implies marked genetic heterogeneity at least in Korean patients with ALS.