tools for splicing defect prediction have a key role to assess the impact of variants of uncertain significance. Our aim was to evaluate the performance of a set of commonly used splicing
tools ...comparing the predictions against RNA
results. This was done for natural splice sites of clinically relevant genes in hereditary breast/ovarian cancer (HBOC) and Lynch syndrome. A study divided into two stages was used to evaluate SSF-like, MaxEntScan, NNSplice, HSF, SPANR, and dbscSNV tools. A discovery dataset of 99 variants with unequivocal results of RNA
studies, located in the 10 exonic and 20 intronic nucleotides adjacent to exon-intron boundaries of
, and
, was collected from four Spanish cancer genetic laboratories. The best stand-alone predictors or combinations were validated with a set of 346 variants in the same genes with clear splicing outcomes reported in the literature. Sensitivity, specificity, accuracy, negative predictive value (NPV) and Mathews Coefficient Correlation (MCC) scores were used to measure the performance. The discovery stage showed that HSF and SSF-like were the most accurate for variants at the donor and acceptor region, respectively. The further combination analysis revealed that HSF, HSF+SSF-like or HSF+SSF-like+MES achieved a high performance for predicting the disruption of donor sites, and SSF-like or a sequential combination of MES and SSF-like for predicting disruption of acceptor sites. The performance confirmation of these last results with the validation dataset, indicated that the highest sensitivity, accuracy, and NPV (99.44%, 99.44%, and 96.88, respectively) were attained with HSF+SSF-like or HSF+SSF-like+MES for donor sites and SSF-like (92.63%, 92.65%, and 84.44, respectively) for acceptor sites. We provide recommendations for combining algorithms to conduct
splicing analysis that achieved a high performance. The high NPV obtained allows to select the variants in which the study by
RNA analysis is mandatory against those with a negligible probability of being spliceogenic. Our study also shows that the performance of each specific predictor varies depending on whether the natural splicing sites are donors or acceptors.
Hereditary leiomyomatosis and renal cell cancer syndrome is a rare autosomal dominant hereditary syndrome. Previously, we published the largest cohort of FH mutation carriers in Spain and observed a ...highly recurrent missense heterozygous variant, FH(NM_000143.4):c.1118A > G p.(Asn373Ser), in 104 individuals from 31 apparently unrelated families. Here, we aimed to establish its founder effect and characterize the associated clinical phenotype.
Haplotype analysis confirmed that families shared a common haplotype (32/38 markers) spanning 0.61-0.82 Mb, indicating this recurrent variant was inherited from a founder ancestor. Cutaneous and uterine leiomyomatosis were diagnosed in 64.6% (64/99) and 98% (50/51) of patients, respectively, and renal cell cancer was present in 10.4% (10/96). The pathogenic FH_c.1118A > G variant is a Spanish founder mutation that originated 12-26 generations ago. We estimate that the variant may have appeared between 1370 and 1720. Individuals carrying this founder mutation had similar frequency of renal cell cancer and a higher frequency of renal cysts and leiomyomas than those in other cohorts of this syndrome.
In the Spanish province of Alicante there is a high prevalence of HLRCC because of the founder mutation FH c.1118A > G; p.(Asn373Ser). The characterization of founder mutations provides accurate and specific information regarding their penetrance and expressivity. In individuals with suspected HLRCC from the province of Alicante, genetic testing by direct analysis of the founder FH c.1118A > G; p.(Asn373Ser) mutation may be a faster and more efficient diagnostic tool compared with complete gene sequencing.
The mechanisms triggering metastasis in pheochromocytoma/paraganglioma are unknown, hindering therapeutic options for patients with metastatic tumors (mPPGL). Herein we show by genomic profiling of a ...large cohort of mPPGLs that high mutational load, microsatellite instability and somatic copy-number alteration burden are associated with ATRX/TERT alterations and are suitable prognostic markers. Transcriptomic analysis defines the signaling networks involved in the acquisition of metastatic competence and establishes a gene signature related to mPPGLs, highlighting CDK1 as an additional mPPGL marker. Immunogenomics accompanied by immunohistochemistry identifies a heterogeneous ecosystem at the tumor microenvironment level, linked to the genomic subtype and tumor behavior. Specifically, we define a general immunosuppressive microenvironment in mPPGLs, the exception being PD-L1 expressing MAML3-related tumors. Our study reveals canonical markers for risk of metastasis, and suggests the usefulness of including immune parameters in clinical management for PPGL prognostication and identification of patients who might benefit from immunotherapy.
Hereditary leiomyomatosis and renal cell cancer syndrome (HLRCC) is a very rare hereditary disorder characterized by cutaneous leiomyomas (CLMs), uterine leiomyomas (ULMs), renal cysts (RCys) and ...renal cell cancers (RCCs). We aimed to describe the genetics, clinical features and potential genotype-phenotype associations in the largest cohort of fumarate hydratase enzyme mutation carriers known from Spain using a multicentre, retrospective study of individuals with a genetic or clinical diagnosis of HLRCC. We collected clinical information from medical records, analysed genetic variants and looked for genotype-phenotype associations. Analyses were performed using R 3.6.0. software. We included 197 individuals: 74 index cases and 123 relatives. CLMs were diagnosed in 65% of patients, ULMs in 90% of women, RCys in 37% and RCC in 10.9%. Twenty-seven different pathogenic variants were detected, 12 (44%) of them not reported previously. Patients with missense pathogenic variants showed higher frequencies of CLMs, ULMs and RCys, than those with loss-of-function variants (p = 0.0380, p = 0.0015 and p = 0.024, respectively). This is the first report of patients with HLRCC from Spain. The frequency of RCCs was lower than those reported in the previously published series. Individuals with missense pathogenic variants had higher frequencies of CLMs, ULMs and RCys.
Colonoscopy reduces colorectal cancer (CRC) incidence and mortality in Lynch syndrome (LS) carriers. However, a high incidence of postcolonoscopy CRC (PCCRC) has been reported. Colonoscopy is highly ...dependent on endoscopist skill and is subject to quality variability. We aimed to evaluate the impact of key colonoscopy quality indicators on adenoma detection and prevention of PCCRC in LS.
We conducted a multicenter study focused on LS carriers without previous CRC undergoing colonoscopy surveillance (n = 893). Incident colorectal neoplasia during surveillance and quality indicators of all colonoscopies were analyzed. We performed an emulated target trial comparing the results from the first and second surveillance colonoscopies to assess the effect of colonoscopy quality indicators on adenoma detection and PCCRC incidence. Risk analyses were conducted using a multivariable logistic regression model.
The 10-year cumulative incidence of adenoma and PCCRC was 60.6% (95% CI, 55.5%-65.2%) and 7.9% (95% CI, 5.2%-10.6%), respectively. Adequate bowel preparation (odds ratio OR, 2.07; 95% CI, 1.06-4.3), complete colonoscopies (20% vs 0%; P = .01), and pan-chromoendoscopy use (OR, 2.14; 95% CI, 1.15-3.95) were associated with significant improvement in adenoma detection. PCCRC risk was significantly lower when colonoscopies were performed during a time interval of less than every 3 years (OR, 0.35; 95% CI, 0.14-0.97). We observed a consistent but not significant reduction in PCCRC risk for a previous complete examination (OR, 0.16; 95% CI, 0.03-1.28), adequate bowel preparation (OR, 0.64; 95% CI, 0.17-3.24), or previous use of high-definition colonoscopy (OR, 0.37; 95% CI, 0.02-2.33).
Complete colonoscopies with adequate bowel preparation and chromoendoscopy use are associated with improved adenoma detection, while surveillance intervals of less than 3 years are associated with a reduction of PCCRC incidence. In LS, high-quality colonoscopy surveillance is of utmost importance for CRC prevention.
Multigene panels provide a powerful tool for analyzing several genes simultaneously. We evaluated the frequency of pathogenic variants (PV) in customized predefined panels according to clinical ...suspicion by phenotype and compared it to the yield obtained in the analysis of our clinical research gene panel. We also investigated mutational yield of opportunistic testing of BRCA1/2 and mismatch repair (MMR) genes in all patients. A total of 1,205 unrelated probands with clinical suspicion of hereditary cancer were screened for germline mutations using panel testing. Overall, 1,048 females and 157 males were analyzed, mean age at cancer diagnosis was 48; 883 had hereditary breast/ovarian cancer‐suspicion, 205 hereditary nonpolyposis colorectal cancer (HNPCC)‐suspicion, 73 adenomatous‐polyposis‐suspicion and 44 with other/multiple clinical criteria. At least one PV was found in 150 probands (12%) analyzed by our customized phenotype‐driven panel. Tumoral MMR deficiency predicted for the presence of germline MMR gene mutations in patients with HNPCC‐suspicion (46/136 vs. 0/56 in patients with and without MMR deficiency, respectively). Opportunistic testing additionally identified five MSH6, one BRCA1 and one BRCA2 carriers (0.6%). The analysis of the extended 24‐gene panel provided 25 additional PVs (2%), including in 4 out of 51 individuals harboring MMR‐proficient colorectal tumors (2 CHEK2 and 2 ATM). Phenotype‐based panels provide a notable rate of PVs with clinical actionability. Opportunistic testing of MMR and BRCA genes leads to a significant straightforward identification of MSH6, BRCA1 and BRCA2 mutation carriers, and endorses the model of opportunistic testing of genes with clinical utility within a standard genetic counseling framework.
What's new?
Multigene panels offer a powerful tool for analyzing several cancer‐related genes with a single test. But which genes are actually useful in guiding medical decisions in the clinic? In this study, the authors analyzed several customized, phenotype‐driven diagnostic gene panels. These yielded a notable rate of pathogenic variants with clear clinical actionability. The study also found that opportunistic testing of MMR and BRCA genes leads to a significant, straightforward identification of MSH6, BRCA1 and BRCA2 mutation carriers. This approach could be applied within a standard genetic counseling framework.
Genetic analysis of
and
for the diagnosis of hereditary breast and ovarian cancer (HBOC) is commonly restricted to coding regions and exon-intron boundaries. Although germline pathogenic variants in ...these regions explain about ~20% of HBOC cases, there is still an important fraction that remains undiagnosed. We have screened
deep intronic regions to identify potential spliceogenic variants that could explain part of the missing HBOC susceptibility.
We analysed
deep intronic regions by targeted gene sequencing in 192 high-risk HBOC families testing negative for
during conventional analysis. Rare variants (MAF <0.005) predicted to create/activate splice sites were selected for further characterisation in patient RNA. The splicing outcome was analysed by RT-PCR and Sanger sequencing, and allelic imbalance was also determined when heterozygous exonic loci were present.
A novel transcript was detected in
c.4185+4105C>T variant carrier. This variant promotes the inclusion of a pseudoexon in mature mRNA, generating an aberrant transcript predicted to encode for a non-functional protein. Quantitative and allele-specific assays determined haploinsufficiency in the variant carrier, supporting a pathogenic effect for this variant. Genotyping of 1030 HBOC cases and 327 controls did not identify additional carriers in Spanish population.
Screening of
intronic regions has identified the first
deep intronic variant associated with HBOC by pseudoexon activation. Although the frequency of deleterious variants in these regions appears to be low, our study highlights the importance of studying non-coding regions and performing comprehensive RNA assays to complement genetic diagnosis.
Clinical and familial factors predict psychological distress after genetic testing for cancer susceptibility. However, the contribution of an individual's psychological background to such distress is ...unclear. This study aims to analyze the psychological impact of genetic testing and to identify the profile of individuals at higher risk. This is a longitudinal multicenter study of individuals undergoing genetic testing for cancer susceptibility. Demographic, clinical, genetic, familial, and psychological (personality types, cancer worry) characteristics were assessed by validated questionnaires the day of genetic testing. Distress, uncertainty, and positive experience perception (MICRA scale) were evaluated at the results disclosure visit, and 3 and 12 months afterwards. Multivariate analysis was performed. A total of 714 individuals were included. A high neuroticism score, high baseline cancer worry, and a positive genetic test result were independently associated with higher psychological impact (p-value < 0.05). The highest risk profile (10% of the cohort) included women with high level of neuroticism and a positive result. Uncertainty was mainly associated with a high level of neuroticism, regardless of the genetic test result. A holistic approach to personalized germline genetic counseling should include the assessment of personality dimensions.
Purpose
Few and small studies have been reported about multigene testing usage by massively parallel sequencing in European cancer families. There is an open debate about what genes should be tested, ...and the actionability of some included genes is under research.
Methods
We investigated a panel of 34 known high/moderate-risk cancer genes, including 16 related to breast or ovarian cancer (BC/OC) genes, and 63 candidate genes to BC/OC in 192 clinically suspicious of hereditary breast/ovarian cancer (HBOC) Spanish families without pathogenic variants in
BRCA1
or
BRCA2
(
BRCA1
/
2
).
Results
We identified 16 patients who carried a high- or moderate-risk pathogenic variant in eight genes: 4
PALB2
, 3
ATM
, 2
RAD51D
, 2
TP53
, 2
APC
, 1
BRIP1
, 1
PTEN
and 1
PMS2
. These findings led to increased surveillance or prevention options in 12 patients and predictive testing in their family members. We detected 383 unique variants of uncertain significance in known cancer genes, of which 35 were prioritized in silico. Eighteen loss-of-function variants were detected in candidate BC/OC genes in 17 patients (1
BARD1
, 1
ERCC3
, 1
ERCC5
, 2
FANCE
, 1
FANCI
, 2
FANCL
, 1
FANCM
, 1
MCPH1
, 1
PPM1D
, 2
RBBP8
, 3
RECQL4
and 1 with
SLX4
and
XRCC2
), three of which also carry pathogenic variants in known cancer genes.
Conclusions
Eight percent of the
BRCA1
/
2
negative patients carry pathogenic variants in other actionable genes. The multigene panel usage improves the diagnostic yield in HBOC testing and it is an effective tool to identify potentially new candidate genes.
Many BRCA1 and BRCA2 (BRCA1/2) genetic variants have been studied at mRNA level and linked to hereditary breast and ovarian cancer due to splicing alteration. In silico tools are reliable when ...assessing variants located in consensus splice sites, but we may identify variants in complex genomic contexts for which bioinformatics is not precise enough. In this study, we characterize BRCA2 c.7976 + 5G > T variant located in intron 17 which has an atypical donor site (GC). This variant was identified in three unrelated Spanish families and we have detected exon 17 skipping as the predominant transcript occurring in carriers. We have also detected several isoforms (Δ16‐18, Δ17,18, Δ18, and ▼17q224) at different expression levels among carriers and controls. This study remarks the challenge of interpreting genetic variants when multiple alternative isoforms are present, and that caution must be taken when using in silico tools to identify potential spliceogenic variants located in GC‐AG introns.
In this study we characterize BRCA2 c.7976 + 5G > T variant located in intron 17, which has an atypical donor site (GC). The variant promotes exon 17 skipping, but several isoforms (Δ16‐18, Δ17,18, Δ18, and ▼17q224) have also been detected at different expression levels in variant carriers and controls. This study remarks the challenge of interpreting genetic variants located in regions with high levels of alternative splicing.
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