Incidental findings in a series of 2500 gene panel tests for a genetic predisposition to cancer: Results and impact on patients

Secondary findings in hereditary cancer genes after germline genetic testing - systematic review of literature

In the last decade the increasing use of germline genetic testing has led to frequent discoveries of secondary findings (SF) in hereditary cancer (HC) genes. Disclosure and clinical management of such findings are still not clearly defined and raise many ethical, clinical, and practical questions. This systematic review is focused on frequency of reported SF in HC genes across different populations as well as summarizing current guidelines, recommendations, and actual clinical practice about reporting and managing SF in HC genes. A systematic literature search according to the PRISMA guidelines was performed on the electronic database PubMed from inception to June 2024. 30 research papers involving almost 150,000 patients were reviewed. The reported frequencies of SF in HC genes varied between 0.4 and 3.1%. The majority of patients agreed to receive SF for medically actionable genes. Management and surveillance of patients after disclosure of SF in HC genes were rarely reported, but the limited data show no regret of receiving such results as well as diagnoses of early-stage cancer in patients participating in recommended surveillance programs related to SF. A substantial number of carriers of highly penetrant pathogenic variants in HC genes is discovered by reporting SF after germline genetic testing with next-generation sequencing. Additional information about the impact of SF disclosure on individuals and health care systems is needed to optimize the integration of SF into clinical care.

Variants that get straight to your heart - Cardiogenetic secondary findings in exome sequencing

BACKGROUND

Exome sequencing has been established as a fundamental tool in genetic diagnostics. It may also provide information about variants in genes unrelated to the primary purpose, so-called secondary findings. Especially, diagnoses of unnoticed inborn cardiac diseases are of high clinical relevance due to therapeutic options in context of prevention of sudden cardiac death.

METHODS

Exome data of 9962 individuals was analysed for relevant cardiogenetic findings. Genes were selected according to ACMG recommendations for secondary findings (v.3.1). First, a filter for (likely) pathogenic variants, published in the ClinVar database, was used. Second, exome data was screened for loss of function (LoF) variants in genes in which LoF is a known disease pathomechanism. All variants were evaluated by geneticists regarding their pathogenicity.

RESULTS

Pathogenic or likely pathogenic variants were identified in 136 different individuals (136/9962, 1.4%), with the Low-Density Lipoprotein Receptor gene (LDLR, 24/136, 17.6%) and the Titin gene (TTN, 24/136, 17.6%), being the most frequently affected ones. 31.6% (43/136) of the identified variants had been reported beforehand, while 47.1% (64/136) had not been reported. The remaining cases (29/136, 21.3%) were part of research projects with no written reports. In 26.5% (36/136), the finding would have been missed, if only index patients and not their parents had been screened for secondary findings in case of trio ES.

CONCLUSION

As demonstrated in our study, at least one or two out of one hundred people are likely to carry a pathogenic cardiogenetic variant. Counselling geneticist and clinicians need to be aware of these findings in exome and genome sequencing. Informed consent of the patient regarding the report of secondary findings should absolutely be obtained beforehand.

Comprehensive Clinical Genetics, Molecular and Pathological Evaluation Efficiently Assist Diagnostics and Therapy Selection in Breast Cancer Patients with Hereditary Genetic Background

Using multigene panel testing for the diagnostic evaluation of patients with hereditary breast and ovarian cancer (HBOC) syndrome often identifies clinically actionable variants in genes with varying levels of penetrance. High-penetrance genes (BRCA1, BRCA2, CDH1, PALB2, PTEN, STK11, TP53) inform specific clinical surveillance and therapeutic decisions, while recommendations for moderate-penetrance genes (ATM, BARD1, BRIP1, CHEK2, MLH1, MSH2, MSH6, PMS2, EPCAM, NF1, RAD51C, RAD51D) are more limited. A detailed disease history, including pedigree data, helps formulate the most appropriate and personalised management strategies. In this study, we evaluated the clinical benefits of comprehensive hereditary cancer gene panel testing and a pre-sent questionnaire in Hungarian patients with suspected HBOC syndrome. We prospectively enrolled 513 patients referred for HBOC testing. Of these, 463 met the genetic testing criteria, while 50 did not but were tested due to potential therapeutic indications. Additionally, a retrospective cohort of 47 patients who met the testing criteria but had previously only been tested for BRCA1/2 was also analysed. Among the 463 patients in the prospective cohort, 96 (20.7%) harboured pathogenic/likely pathogenic (P/LP) variants-67 in high-penetrance genes and 29 in moderate-penetrance genes. This ratio was similar in the retrospective cohort (6/47; 12.7%). In patients who did not meet the testing criteria, no mutations in high-penetrance genes were found, and only 3 of 50 (6%) harboured P/LP variants in moderate-penetrance genes. Secondary findings (P/LP variants in non-HBOC-associated genes) were identified in two patients. In the prospective cohort, P/LP variants in BRCA1 and BRCA2 were the most prevalent (56/96; 58.3%), and the extended testing doubled the P/LP detection ratio. Among moderate-penetrance genes, five cases (three in the prospective and two in the retrospective cohorts) had P/LP variants in Lynch syndrome-associated genes. Further immunohistochemistry analysis of breast tumour tissues helped clarify the causative role of these variants. Comprehensive clinical and molecular genetic evaluation is beneficial for the diagnosis and management of patients with P/LP variants in hereditary tumour-predisposing genes and can serve as a basis for effective therapy selection, such as PARP inhibitors or immunotherapy.

Medulloblastoma and other neoplasms in patients with heterozygous germline SUFU variants: A scoping review

In 2002, heterozygous suppressor of fused variants (SUFU+/-) in the germline were described to have a tumor suppressor role in the development of pediatric medulloblastoma (MB). Other neoplasms associated with pathologic germline SUFU+/- variants have also been described among patients with basal cell nevus syndrome (BCNS; BCNS is also known as Gorlin syndrome, nevoid basal cell carcinoma [BCC] syndrome or Gorlin-Goltz syndrome; OMIM 109400), an autosomal-dominant cancer predisposition syndrome. The phenotype of patients with germline SUFU+/- variants is very poorly characterized due to a paucity of large studies with long-term follow-up. As such, there is a clinical need to better characterize the spectrum of neoplasms among patients with germline SUFU+/- variants so that clinicians can provide accurate counseling and optimize tumor surveillance strategies. The objective of this study is to perform a scoping review to map the evidence on the rate of medulloblastoma and to describe the spectrum of other neoplasms among patients with germline SUFU+/- variants. A review of all published literature in PubMed (MEDLINE), EMBASE, Cochrane, and Web of Science were searched from the beginning of each respective database until October 9, 2021. Studies of pediatric and adult patients with a confirmed germline SUFU+/- variant who were evaluated for the presence of any neoplasm (benign or malignant) were included. There were 176 patients (N = 30 studies) identified with a confirmed germline SUFU+/- variant who met inclusion criteria. Data were extracted from two cohort studies, two case-control studies, 18 case series, and eight case reports. The median age at diagnosis of a germline SUFU+/- variant was 4.5 years where 44.4% identified as female and 13.4% of variants were de novo. There were 34 different neoplasms (benign and malignant) documented among patients with confirmed germline SUFU+/- variants, and the most common were medulloblastoma (N = 59 patients), BCC (N = 21 patients), and meningioma (N = 19 patients). The median age at medulloblastoma diagnosis was 1.42 years (range 0.083-3; interquartile range 1.2). When data were available for these three most frequent neoplasms (N = 95 patients), 31 patients (32.6%) had neither MB, BCC nor meningioma; 51 patients (53.7%) had one of medulloblastoma or BCC or meningioma; eight patients (8.4%) had two of medulloblastoma or BCC or meningioma, and five patients (5.3%) had medulloblastoma and BCC and meningioma. This is the first study to synthesize the data on the frequency and spectrum of neoplasms specifically among patients with a confirmed germline SUFU+/- variant. This scoping review is a necessary step forward in optimizing evidence-based tumor surveillance strategies for medulloblastoma and estimating the risk of other neoplasms that could impact patient outcomes.

A framework for the evaluation and reporting of incidental findings in clinical genomic testing

Currently, there are no widely accepted recommendations in the genomics field guiding the return of incidental findings (IFs), defined here as unexpected results that are unrelated to the indication for testing. Consequently, reporting policies for IFs among laboratories offering genomic testing are variable and may lack transparency. Herein we describe a framework developed to guide the evaluation and return of IFs encountered in probands undergoing clinical genome sequencing (cGS). The framework prioritizes clinical significance and actionability of IFs and follows a stepwise approach with stopping points at which IFs may be recommended for return or not. Over 18 months, implementation of the framework in a clinical laboratory facilitated the return of actionable IFs in 37 of 720 (5.1%) individuals referred for cGS, which is reduced to 3.1% if glucose-6-phosphate dehydrogenase (G6PD) deficiency is excluded. This framework can serve as a model to standardize reporting of IFs identified during genomic testing.

Psychological impact of additional findings detected by genome-wide Non-Invasive Prenatal Testing (NIPT): TRIDENT-2 study

In the Netherlands, genome-wide non-invasive prenatal testing (NIPT) is offered to all pregnant women as part of the nationwide TRIDENT-2 study. Findings other than trisomy 21, 18, or 13, which are called "additional findings", are reported only on request of the pregnant woman. This study examined: (1) women's pre-test perceptions and reasons to opt for additional findings and (2) women's experiences with- and the psychological impact of being informed about an additional finding. A questionnaire, consisting of the anxiety measure State-Trait Anxiety Inventory (STAI), distress measure Impact of Event Scale (IES) and questions developed specifically for this study, was retrospectively administered to 402 women who received an additional finding. A total of 227 (56.5%) women completed the questionnaire. Most (60.2%) chose to know additional findings because they wanted as much information as possible about the health of their fetus. Almost all (92%) stated that receiving the additional finding was unexpected, a shock, and/or they were in disbelief, for 85% it caused a lot of worry. Post-test, high anxiety (STAI) levels were reported in 15.5% of women, and 7.5% reported severe distress (IES). Women who gave birth to an affected child (n = 10) experienced most psychological impact (STAI and IES). Eighty-six percent of women with a fetal aberration would opt for additional findings again, compared to 49.2% of women whose result was confined to the placenta. Pre-test counseling should focus on explaining the different results NIPT can generate. Post-test counseling should focus on guiding pregnant women through this uncertain and anxious time.

Advancing precision oncology through systematic germline and tumor genetic analysis: The oncogenetic point of view on findings from a prospective multicenter clinical trial of 666 patients

INTRODUCTION

With the emergence of targeted therapies, there is a need to accurately identify more tumor biomarkers. The EXOMA trial was designed to offer tumor and germline exome sequencing (ES) to patients with solid malignant tumors and facing therapeutic failure. As hereditary cancer predispositions could be identified, with genetic counseling and health management implications, a genetic consultation was systematically established. This design needs to be discussed as genetic human resources are limited and indication of theranostic tests will increase.

METHODS

Genetic counseling was conducted within 15 days following inclusion in the study for patients recruited between December 2015 and July 2019. In silico analyses from theranostic ES were limited to 317 genes involved in oncogenesis, from both tumor and blood DNA.

RESULTS

Six hundred and sixty six patients had a genetic consultation before ES. In 65/666 patients, 66 germline pathogenic or likely pathogenic (P/LP) variants were identified in 16 actionable genes and seven non-actionable genes according to French guidelines. 24/65 patients had previously received genetic analysis for diagnostic purposes, and for 17 of them, a P/LP variant had already been identified. Among the 48/65 remaining cases for which the EXOMA protocol revealed a previously unknown P/LP variant, only 19 met the criteria for genetic testing for inherited cancer risk after familial survey. These criteria had not been identified by the oncologist in 10 cases. In 21/65 cases, the variant was considered incidental.

DISCUSSION

In 7.4% of patients, an undiagnosed hereditary genetic predisposition was identified, whether or not related to the clinical presentation, and germline analysis impacted oncological management for only 6.3% of the cohort. This low percentage should be weighed against the burden of systematic genetic consultation and urgent circuits. Information or training tools to form oncologists to the prescription of germline genetic analyses should be explored, as well as information supports and patient preferences.

La médecine prédictive à l’épreuve de l’oncohématologie : réflexions à partir de la clinique

Le développement de l’oncogénétique permet de mieux adapter le traitement pour les patients atteints de cancer et aussi de proposer, dans les cas d’anomalies génétiques héréditaires, un suivi adapté aux proches concernés. Néanmoins, les nouvelles technologies de séquençage suscitent des questions éthiques et cliniques, notamment quant à l’impact psychologique de ces tests génétiques. Nous abordons la spécificité de l’identification de mutations génétiques constitutionnelles dans le cadre de l’oncohématologie.