The influence of BRCA variants of unknown significance on cancer risk management decision-making

An overview of actionable and potentially actionable TSC1 and TSC2 germline variants in an online Database

Tuberous Sclerosis Complex (TSC) is caused by loss of function germline variants in the TSC1 or TSC2 tumor suppressor genes. Genetic testing for the detection of pathogenic variants in either TSC1 or TSC2 was implemented as a diagnostic criterion for TSC. However, TSC molecular diagnosis can be challenging due to the absence of variant hotspots and the high number of variants described. This review aimed to perform an overview of TSC1/2 variants submitted in the ClinVar database. Variants of uncertain significance (VUS), missense and single nucleotide variants were the most frequent in clinical significance (37-40%), molecular consequence (37%-39%) and variation type (82%-83%) categories in ClinVar in TSC1 and TSC2 variants, respectively. Frameshift and nonsense VUS have potential for pathogenic reclassification if further functional and segregation studies were performed. Indeed, there were few functional assays deposited in the database and literature. In addition, we did not observe hotspots for variation and many variants presented conflicting submissions regarding clinical significance. This study underscored the importance of disseminating molecular diagnostic results in a public database to render the information largely accessible and promote accurate diagnosis. We encourage the performance of functional studies evaluating the pathogenicity of TSC1/2 variants.

Genetic analysis of oligo-recurrence breast cancer: correlation with clinical outcomes

BACKGROUND

We aimed to identify the relationship between the genomic characteristics and clinical outcomes of oligo-metastatic breast cancer.

METHODS

Oligo-metastatic breast cancer diagnosed by pathology from January 2001 and August 2019 were reviewed and we matched the poly-metastatic patients based on the clinicopathological features of patients included. Clinicopathological values and data of genomic alterations were collected. Oligo-recurrence (oligo-R) was defined as a situation where disease progression occurred in less than 5 anatomical sites and other anatomic areas still suppressed by the ongoing therapy.

RESULTS

A total of 26 breast cancer patients were enrolled in our study, including 14 patients with strict oligo-metastatic disease (oligo-R > 6 months) and 12 with simultaneous poly-metastatic disease. PIK3CA, TP53 and ERBB2 were the most common shared alterations identified in patients included. Based on the median time of oligo-R, we divided the patients with oligo-metastasis into longer oligo-R group (oligo-R > 31.04 months) and shorter oligo-R group (oligo-R ≤ 31.04 months). The analysis of PIK3CA mutation sites showed that H1047R mutation was closely associated with oligo-metastasis, rather than poly-metastasis. H1047R mutation also predicted a better prognosis (oligo-R > 31.04 months) in oligo-metastatic breast cancer. In addition, HER2 positive was more likely to be related to a good outcome in patients with oligo-metastasis.

CONCLUSIONS

Through the genetic analysis of samples from oligo-metastasis, we found the prognostic values of PIK3CA H1047R and HER2 in oligo- and poly-metastasis. We improved the stratification of prognosis and provided new insights for biological behaviors of oligo-metastatic breast cancer.

Challenges in periodic revision of genetic testing results: Comparison of the main classification guidelines and report of a retrospective analysis involving BRCA1/BRCA2 variants of uncertain significance

In the context of cancer predisposition syndromes, it is widely known that the correct interpretation of germline variants identified in multigene panel testing is essential for adequate genetic counseling and clinical decision making, in which variants of uncertain significance (VUS) are not considered actionable findings. Thus, their periodic re-evaluation using appropriate guidelines is notably important. In the present study, we compared the performance of the main variant classification guidelines (ACMG, Sherloc and ENIGMA) in variant reassessment, using as input a BRCA1/2 VUS case series (retrospective analysis) from Brazil, an ethnically diverse and admixed country with substantial challenges in VUS reclassification. As main findings, two of the 15 VUS analyzed were reclassified as likely pathogenic by the 3 guidelines, BRCA1 c.4987-3C > G (rs397509213) and BRCA2 c.7868A > G (rs80359012). Moreover, challenges in variant classification and reassessment are described and additional in silico data about structural impact of the variant BRCA2 c.7868A > G are provided. We hypothesize that the establishment of a framework to reassess VUS could improve this process in health centers that have not yet implemented this practice. Results of this study underscore that periodic monitoring of the functional, clinical, and bioinformatics data of a VUS by a multidisciplinary team are of utmost importance in clinical practice. When there is a specific guideline for a given gene, such as ENIGMA for BRCA1/2, it should be considered the first option for variant assessment. Finally, recruitment of VUS carriers and their relatives to participate in variant segregation studies and publication of VUS reclassification results in the international scientific literature should be encouraged.

Germline Mutations Landscape in a Cohort of the State of Minas Gerais, Brazil, in Patients Who Underwent Genetic Counseling for Gynecological and Breast Cancer

OBJECTIVE

 The present study evaluated the profile of germline mutations present in patients who underwent genetic counseling for risk assessment for breast cancer (BC), ovarian cancer (OC), and endometrial cancer (EC) with a possible hereditary pattern.

METHODS

 Medical records of 382 patients who underwent genetic counseling after signing an informed consent form were analyzed. A total of 55.76% of patients (213/382) were symptomatic (personal history of cancer), and 44.24% (169/382) were asymptomatic (absence of the disease). The variables analyzed were age, sex, place of birth, personal or family history of BC, OC, EC, as well as other types of cancer associated with hereditary syndromes. The Human Genome Variation Society (HGVS) nomenclature guidelines were used to name the variants, and their biological significance was determined by comparing 11 databases.

RESULTS

 We identified 53 distinct mutations: 29 pathogenic variants, 13 variants of undetermined significance (VUS), and 11 benign. The most frequent mutations were BRCA1 c.470_471delCT, BRCA1 c.4675 + 1G > T, and BRCA2 c.2T> G. Furthermore, 21 variants appear to have been described for the first time in Brazil. In addition to BRCA1/2 mutations, variants in other genes related to hereditary syndromes that predispose to gynecological cancers were found.

CONCLUSION

 This study allowed a deeper understanding of the main mutations identified in families in the state of Minas Gerais and demonstrates the need to assess the family history of non-gynecological cancer for risk assessment of BC, OC, and EC. Moreover, it is an effort that contributes to population studies to evaluate the cancer risk mutation profile in Brazil.

Assessing the pathogenicity of BRCA1/2 variants of unknown significance: Relevance and challenges for breast cancer precision medicine

Introduction

Breast cancer (BC) is the leading cause of cancer-related death in women worldwide. Pathogenic variants in BRCA1 and BRCA2 genes account for approximately 50% of all hereditary BC, with 60-80% of patients characterized by Triple Negative Breast Cancer (TNBC) at an early stage phenotype. The identification of a pathogenic BRCA1/2 variant has important and expanding roles in risk-reducing surgeries, treatment planning, and familial surveillance. Otherwise, finding unclassified Variants of Unknown Significance (VUS) limits the clinical utility of the molecular test, leading to an "imprecise medicine".

Methods

We reported the explanatory example of the BRCA1 c.5057A>C, p.(His1686Pro) VUS identified in a patient with TNBC. We integrated data from family history and clinic-pathological evaluations, genetic analyses, and bioinformatics in silico investigations to evaluate the VUS classification.

Results

Our evaluation posed evidences for the pathogenicity significance of the investigated VUS: 1) association of the BRCA1 variant to cancer-affected members of the family; 2) absence of another high-risk mutation; 3) multiple indirect evidences derived from gene and protein structural analysis.

Discussion

In line with the ongoing efforts to uncertain variants classification, we speculated about the relevance of an in-depth assessment of pathogenicity of BRCA1/2 VUS for a personalized management of patients with BC. We underlined that the efficient integration of clinical data with the widest number of supporting molecular evidences should be adopted for the proper management of patients, with the final aim of effectively guide the best prognostic and therapeutic paths.

Experiences of individuals with a variant of uncertain significance on genetic testing for hereditary cancer risks: a mixed method systematic review

The expansion of Multi-Gene Panel Testing (MGPT) has led to increased detection of variants of uncertain significance (VUS) among individuals with personal or family history of cancer. However, having a VUS result can impact on emotional and psychological wellbeing and cause challenges for non-geneticist healthcare providers. The purpose of this mixed methods systematic review was to examine what is currently known about the experiences of individuals with a VUS on genetic testing for inherited cancer susceptibility. The initial search was conducted in June 2020 using PUBMED, CINAHL, Web of Science, and PsychInfo according to the Joanna Briggs methodology for systematic reviews. A total of 18 studies met the inclusion criteria. Studies included in this review identified a range of emotional reactions to a VUS result, a general lack of understanding of a VUS result and its implications, frustration with a lack of healthcare provider knowledge, and a need for clear communication with healthcare providers. This review identified critical gaps in current knowledge to guide genetic counseling praxis, specifically in the knowledge of communication patterns and methods of improving communication with healthcare providers and family members and preferred risk management strategies. This will help to improve the counseling process and the management of care during and after genetic testing.

BRCA1/2 variants of unknown significance in hereditary breast and ovarian cancer (HBOC) syndrome: looking for the hidden meaning

Hereditary breast and ovarian cancer syndrome is caused by germline mutations in BRCA1/2 genes. These genes are very large and their mutations are heterogeneous and scattered throughout the coding sequence. In addition to the above-mentioned mutations, variants of uncertain/unknown significance (VUSs) have been identified in BRCA genes, which make more difficult the clinical management of the patient and risk assessment. In the last decades, several laboratories have developed different databases that contain more than 2000 variants for the two genes and integrated strategies which include multifactorial prediction models based on direct and indirect genetic evidence, to classify the VUS and attribute them a clinical significance associated with a deleterious, high-low or neutral risk. This review provides a comprehensive overview of literature studies concerning the VUSs, in order to assess their impact on the population and provide new insight for the appropriate patient management in clinical practice.

BRCA1/BRCA2 variants of uncertain significance in clinical practice: A case report

The influence of BRCA1/2 variants of uncertain significance (VUSs) on the cancer risk and their association with the response to treatment is uncertain. The aim of the present study was to evaluate the role of BRCA VUS in patients with breast cancer. A total of two cases of breast cancer patients with the BRCA VUS were described. The complete coding sequence of BRCA1/2 genes was analyzed from the genomic DNA material by next generation sequencing on the Ion Torrent platform. The presence of c.3454G>A (p.Asp1152Asn) VUS in the BRCA1 gene was reported in a 64-year-old woman with invasive breast carcinoma. The characteristics of the breast tumors were the following: moderately differentiated-intermediate grade (NG-2 G-2), HER2 (+), estrogen receptor (ER) (+++), progesterone receptor (PR) (+++), luminal A subtype and pT2 N1a Mx. The second detected VUS was the c.2374T>C (p.Tyr792His) variant in the BRCA2 gene. This variant was reported in a 33-year-old woman who was diagnosed with right breast cancer (cT2N1M0). The invasive breast carcinoma was characterized as follows: NG-2 G-2, ER (+++), PR (+++), Ki-67 10%, HER2 (+++) and luminal B subtype. The data demonstrated that patients with VUSs should be managed based on their family history of cancer and clinicopathological characteristics. The clinical significance of the VUS in BRCA1/2 may change over time and reclassification of the variant to 'pathogenic' or 'benign' should be undertaken. Patients with VUS should be followed up regularly.

Clinical management among individuals with variant of uncertain significance in hereditary cancer: A systematic review and meta-analysis

Improper medical use of variant of uncertain significance (VUS) remains a concern in hereditary cancer genetic testing. The goal of this study was to assess the association between pathogenic and likely pathogenic (P/LP), VUS, and benign and likely benign (B/LB) genetic test results and cancer-related surgical and screening management. Systematic searches of Medline, Embase, EBSCO CINAHL Plus, and PsycINFO were conducted from 1946 to August 26, 2020. Eligible studies included individuals with cancer genetic test result and surgical or screening management outcomes. We reviewed 885 abstracts and 22 studies that reported relevant surgical and screening outcomes were included. Meta-analysis revealed significantly higher surgical rates among individuals with P/LP than among those with VUS for therapeutic mastectomy with contralateral prophylactic mastectomy (OR = 7.35, 95% CI, 4.14-13.64), prophylactic mastectomy (OR = 3.05, 95% CI, 1.5-6.19), and oophorectomy (OR = 6.46, 95% CI, 3.64-11.44). There were no significant differences in therapeutic mastectomy, or breast conservation or lumpectomy rates between individuals with P/LP and VUS, or in any outcomes between patients with VUS and B/LB. Studies evaluating screening outcomes were limited, and results were conflicting. Comprehensive analysis do not indicate that a significant number of individuals with VUS results undergo inappropriate clinical management.

Prevalence and predictors of germline BRCA1 and BRCA2 mutations among young patients with breast cancer in Jordan

BRCA1 and BRCA2 mutations are not uncommon in breast cancer patients. Western studies show that such mutations are more prevalent among younger patients. This study evaluates the prevalence of germline mutations in BRCA1 and BRCA2 among breast cancer patients diagnosed at age 40 or younger in Jordan. Blood samples of patients with breast cancer diagnosed at age 40 years or younger were obtained for DNA extraction and BRCA sequencing. Mutations were classified as benign/likely benign (non-carrier), pathogenic/likely pathogenic variant (carrier) and variant of uncertain significance (VUS). Genetic testing and counseling were completed on 616 eligible patients. Among the whole group, 75 (12.2%) had pathogenic or likely pathogenic variants; two of the BRCA2 mutations were novel. In multivariate analysis, triple-negative disease (Odd Ratio [OR]: 5.37; 95% CI 2.88-10.02, P < 0.0001), breast cancer in ≥ 2 family members (OR: 4.44; 95% CI 2.52-7.84, P < 0.0001), and a personal history ≥ 2 primary breast cancers (OR: 3.43; 95% CI 1.62-7.24, P = 0.001) were associated with higher mutation rates. In conclusion, among young Jordanian patients with breast cancer, mutation rates are significantly higher in patients with triple-negative disease, personal history of breast cancer and those with two or more close relatives with breast cancer.

Prevalence and Spectrum of Germline BRCA1 and BRCA2 Variants of Uncertain Significance in Breast/Ovarian Cancer: Mysterious Signals From the Genome

About 10–20% of breast/ovarian (BC/OC) cancer patients undergoing germline BRCA1/2 genetic testing have been shown to harbor Variants of Uncertain Significance (VUSs). Since little is known about the prevalence of germline BRCA1/2 VUS in Southern Italy, our study aimed at describing the spectrum of these variants detected in BC/OC patients in order to improve the identification of potentially high-risk BRCA variants helpful in patient clinical management. Eight hundred and seventy-four BC or OC patients, enrolled from October 2016 to December 2020 at the “Sicilian Regional Center for the Prevention, Diagnosis and Treatment of Rare and Heredo-Familial Tumors” of University Hospital Policlinico “P. Giaccone” of Palermo, were genetically tested for germline BRCA1/2 variants through Next-Generation Sequencing analysis. The mutational screening showed that 639 (73.1%) out of 874 patients were BRCA-w.t., whereas 67 (7.7%) were carriers of germline BRCA1/2 VUSs, and 168 (19.2%) harbored germline BRCA1/2 pathogenic/likely pathogenic variants. Our analysis revealed the presence of 59 different VUSs detected in 67 patients, 46 of which were affected by BC and 21 by OC. Twenty-one (35.6%) out of 59 variants were located on BRCA1 gene, whereas 38 (64.4%) on BRCA2. We detected six alterations in BRCA1 and two in BRCA2 with unclear interpretation of clinical significance. Familial anamnesis of a patient harboring the BRCA1-c.3367G>T suggests for this variant a potential of pathogenicity, therefore it should be carefully investigated. Understanding clinical significance of germline BRCA1/2 VUS could improve, in future, the identification of potentially high-risk variants useful for clinical management of BC or OC patients and family members.

AMLVaran: a software approach to implement variant analysis of targeted NGS sequencing data in an oncological care setting

BACKGROUND

Next-Generation Sequencing (NGS) enables large-scale and cost-effective sequencing of genetic samples in order to detect genetic variants. After successful use in research-oriented projects, NGS is now entering clinical practice. Consequently, variant analysis is increasingly important to facilitate a better understanding of disease entities and prognoses. Furthermore, variant calling allows to adapt and optimize specific treatments of individual patients, and thus is an integral part of personalized medicine.However, the analysis of NGS data typically requires a number of complex bioinformatics processing steps. A flexible and reliable software that combines the variant analysis process with a simple, user-friendly interface is therefore highly desirable, but still lacking.

RESULTS

With AMLVaran (AML Variant Analyzer), we present a web-based software, that covers the complete variant analysis workflow of targeted NGS samples. The software provides a generic pipeline that allows free choice of variant calling tools and a flexible language (SSDL) for filtering variant lists. AMLVaran's interactive website presents comprehensive annotation data and includes curated information on relevant hotspot regions and driver mutations. A concise clinical report with rule-based diagnostic recommendations is generated.An AMLVaran configuration with eight variant calling tools and a complex scoring scheme, based on the somatic variant calling pipeline appreci8, was used to analyze three datasets from AML and MDS studies with 402 samples in total. Maximum sensitivity and positive predictive values were 1.0 and 0.96, respectively. The tool's usability was found to be satisfactory by medical professionals.

CONCLUSION

Coverage analysis, reproducible variant filtering and software usability are important for clinical assessment of variants. AMLVaran performs reliable NGS variant analyses and generates reports fulfilling the requirements of a clinical setting. Due to its generic design, the software can easily be adapted for use with different targeted panels for other tumor entities, or even for whole-exome data. AMLVaran has been deployed to a public web server and is distributed with Docker scripts for local use.

Prevalence and oncologic outcomes of BRCA1/2 mutation and variant of unknown significance in epithelial ovarian carcinoma patients in Korea

Objective

BRCA mutational status is important in the management of ovarian cancer, but there is a lack of evidence supporting genetic testing in Asian populations. This study was performed to investigate the prevalence and prognostic outcomes of BRCA1/2 mutation and variant of unknown significance (VUS) in Korean patients diagnosed with epithelial ovarian cancer (EOC).

Methods

Among patients newly diagnosed with EOC between January 2007 and January 2017, those tested for germline BRCA1/2 mutation were studied, regardless of family history. Overall survival (OS) and progression-free survival (PFS) were compared between the patients with and without BRCA1/2 mutation and VUS.

Results

A total of 313 patients underwent BRCA testing: 88 patients had a BRCA1/2 mutation and 48 patients had a BRCA1/2 VUS (28.1% and 15.3%, respectively). There were no significant associations between BRCA1/2 mutation, BRCA1/2 wild-type, or BRCA1/2 VUS with age at diagnosis, histologic distribution, or residual disease status after primary cytoreductive surgery. BRCA1 mutation, including BRCA1 VUS, showed no difference in PFS or OS compared to BRCA1 wild-type. In contrast, BRCA2 mutation showed longer PFS than that of BRCA2 wild-type (P=0.04) or BRCA2 VUS (P=0.02). BRCA2 mutation, including BRCA2 VUS, did not show any difference in OS compared to BRCA2 wild-type.

Conclusion

BRCA mutation and BRCA VUS had similar clinical characteristics and survival outcomes, except that BRCA2 mutation showed better PFS. The results of this study will help to understand the prognostic significance of BRCA mutation and VUS in Korean patients.