ABSTRACT
Invasive lobular carcinomas (ILCs) have a low frequency of ERBB2 amplification, therefore restricting the use of conventional anti-HER2 therapies for this histologic special type. Conversely, ILCs with low HER2 overexpression may represent a broader target for the use of emerging antibody drug conjugate therapies targeting HER2, since these treatments have proven effective in HER2-low breast cancers. Very scarce data about HER2-low ILCs have been so far published, although these tumors could have different prevalence and histomolecular specificities compared with invasive breast carcinoma of no special type (IBC-NST). Our aims in that context were to decipher the clinicopathological and molecular features of a large series of HER2-low ILCs. Comparative evaluation of HER2-low prevalence was done based on a retrospective series of 7970 patients from Institut Curie, with either primary invasive lobular (N = 1103) or no special type (N = 6867) invasive carcinoma. Clinicopathological and molecular analyses of HER2-zero, HER2-low, and HER2-positive ILCs were performed on a subgroup of 251 patients who underwent surgery for a primary ILC between 2005 and 2008. The mutational profile of these 251 cases was determined from RNAseq data. Compared with HER2-negative IBC-NSTs, the HER2-negative ILCs were found to display a higher frequency of HER2-zero cases (59.4% vs 53.7%) and a lower frequency of HER2-low (40.6% vs 46.3%) (P < .001). Clinicopathological features associated with HER2-low status (vs HER2-zero) in ILC were older age, postmenopausal status, nonclassic ILC histological types, higher grade, proliferation, and estrogen receptor expression levels. Survival curve analysis showed a significantly lower risk of local recurrence for HER2-low (vs HER2-zero) ILCs, but no association was found between HER2 status and either breast cancer-specific survival or distant metastasis-free interval. ERBB3 was the unique mutated gene exclusively associated with HER2-low ILCs yet being mutated at a low frequency (7.1%) (false discovery rate < 0.05). In conclusion, HER2-low ILCs exhibit their own particularities, both on clinical-pathological and molecular levels. Our findings call for larger multicenter validation studies.
Subject(s)
Biomarkers, Tumor , Breast Neoplasms , Carcinoma, Lobular , Receptor, ErbB-2 , Humans , Female , Carcinoma, Lobular/genetics , Carcinoma, Lobular/pathology , Carcinoma, Lobular/metabolism , Carcinoma, Lobular/therapy , Carcinoma, Lobular/drug therapy , Receptor, ErbB-2/genetics , Receptor, ErbB-2/metabolism , Breast Neoplasms/pathology , Breast Neoplasms/genetics , Breast Neoplasms/therapy , Middle Aged , Aged , Retrospective Studies , Biomarkers, Tumor/genetics , Biomarkers, Tumor/analysis , Adult , Mutation , Aged, 80 and overABSTRACT
Invasive lobular carcinomas (ILC) are characterized by a loss of E-cadherin expression and CDH1 gene inactivation. Diagnostic reproducibility for this tumor type is currently suboptimal and could be improved by a better understanding of its histomolecular and clinical heterogeneity. We have analyzed the relationship between presence, type or position of CDH1 mutations, E-cadherin expression and clinicopathological features (including outcome) in a retrospective series of 251 primary ILC with long follow-up (median: 9.5 years). The mutational status of E-cadherin gene (CDH1) was determined by RNA sequencing from frozen tumor samples. E-cadherin immunohistochemistry (IHC) was performed with antibodies directed against the intracellular domain (clone 4A2C7) and the extracellular domain (clone NCH38). IHC expression of p120 and ß-catenin was also assessed in E-cadherin diffusely positive cases. Three major patterns of E-cadherin membrane expression were identified by IHC, with good agreement between the two clones (overall concordance: 83.8%, Kappa 0.67): null/focal expression (≤10%) (72.8% of cases for 4A2C7, 83.8% for NCH38), heterogeneous expression (11-89%) (19.2% of cases for 4A2C7, 6.9% for NCH38) and diffuse expression (≥90%) (8% of cases for 4A2C7, 9.3% for NCH38). E-cadherin membranous expression, when present, was abnormal (incomplete labeling and/or reduced intensity). ILC with diffuse E-cadherin expression showed abnormal ß-catenin or p120-catenin staining in 21% of cases. Interestingly, these cases with diffusely expressed E-cadherin had a CDH1 mutation rate as high as the E-cadherin null/focal cases (â¼70%), but were enriched in non-truncating mutations. Regarding CDH1 mutation location, intracytoplasmic domain mutations correlated with a divergent E-cadherin IHC phenotype between the two antibodies (4A2C7 ≤10% / NCH38 ≥10%). Clinico-pathological correlation analyses found that stromal amount (inversely correlated with tumor cellularity) and TILs were less abundant in ILC with E-cadherin null/focal cases. In addition, CDH1 truncating mutations were associated with radio-histological size discordance, and were identified in multivariate survival analysis as an independent poor prognosis factor in terms of metastasis risk and breast cancer related mortality. Overall, our study highlights the importance of the precise mutational status of CDH1 in the clinical, radiological, histological and phenotypic expression of lobular carcinomas. These findings should be taken into account in future attempts to improve diagnostic criteria or methods for ILC, as well as for clinico-biological studies dedicated to this tumor type.
ABSTRACT
BRCA1 and BRCA2 are tumour suppressor genes that have been characterised as predisposition genes for the development of hereditary breast and ovarian cancers among other malignancies. The molecular diagnosis of this predisposition syndrome is based on the detection of inactivating variants of any type in those genes. But in the case of structural variants, functional consequences can be difficult to assess using standard molecular methods, as the precise resolution of their sequence is often impossible with short-read next generation sequencing techniques. It has been recently demonstrated that Oxford Nanopore long-read sequencing technology can accurately and rapidly provide genetic diagnoses of Mendelian diseases, including those linked to pathogenic structural variants. Here, we report the accurate resolution of a germline duplication event of exons 18-20 of BRCA1 using Nanopore sequencing with adaptive sampling target enrichment. This allowed us to classify this variant as pathogenic within a short timeframe of 10 days. This study provides a proof-of-concept that nanopore adaptive sampling is a highly efficient technique for the investigation of structural variants of tumour suppressor genes in a clinical context.
Subject(s)
Breast Neoplasms , Nanopore Sequencing , Female , Humans , Virulence , Genetic Predisposition to Disease , BRCA1 Protein/genetics , BRCA2 Protein/genetics , Genes, BRCA2 , Exons , Breast Neoplasms/genetics , Germ-Line Mutation/genetics , High-Throughput Nucleotide Sequencing/methodsABSTRACT
Breast carcinomas (BC) with osteoclast-like giant cells (OGC) are rare. Despite their distinct stromal features, their molecular characteristics remain unknown. Here, we report comprehensive clinico-pathological and molecular findings for 27 patients diagnosed with BC-OGC at Institut Curie between 2000 and 2021. Seventeen (63%) cases were invasive carcinomas of no special type (IC NST) with OGC (OGC-IC NST), four (15%) were mixed or multifocal cases with and without OGC (OGC-Mixed), and six (22%) were metaplastic carcinomas with OGC (OGC-MC). All OGC-IC NST and OGC-Mixed cases were ER+ HER2- tumors (most being luminal A based on transcriptomic subtyping, when available), while all OGC-MC were triple-negative. The median age at diagnosis was 46, 45 and 62 years for OGC-IC NST, OGC-Mixed and OGC-MC, respectively. Three patients developed distant metastases (one OGC-IC NST, two OGC-Mixed), one of whom died of metastatic disease (OGC-Mixed), and one other patient died of locally advanced disease (OGC-MC). Histopathological evaluation comparing 13 OGC-IC NST and 19 control IC NST without OGC confirmed that OGC-IC NST showed significantly higher density of vessels (by CD34 immunohistochemistry (IHC)), iron deposits (Perls stain), and CD68 and CD163-positive cell infiltrates. Genomic findings for nine OGC-IC NST and four OGC-MC were consistent with the underlying histologic subtype, including activating alterations of the PI3K/AKT/mTOR pathway in 7/13 cases. Using RNA-seq data, differential gene expression analysis between OGC-IC NST (n = 7) and control IC NST without OGC (n = 7) revealed significant overexpression of TNFSF11 (RANK-L), TNFRSF11A (RANK), CSF1 (M-CSF), CSF1R, and genes encoding osteoclastic enzymes (MMP9, ACP5, CTSK, CTSB) in OGC-IC NST, while OPG (osteoprotegerin) was underexpressed. We also confirmed for the first time RANK-L expression in BC with OGC by IHC (seen in 15 out of 16 cases, and only in 2 of 16 controls without OGC). These findings could offer a rationale for further investigating RANK-L as a therapeutic target in BC with OGC.
Subject(s)
Breast Neoplasms , Carcinoma , RANK Ligand , Female , Humans , Breast Neoplasms/pathology , Carcinoma/pathology , Giant Cells/pathology , Iron , Macrophage Colony-Stimulating Factor , Matrix Metalloproteinase 9 , Osteoclasts/pathology , Osteoprotegerin , Phosphatidylinositol 3-Kinases , Proto-Oncogene Proteins c-akt , TOR Serine-Threonine Kinases , RANK Ligand/geneticsABSTRACT
Microsatellite instability (MSI) is a genetic alteration due to a deficiency of the DNA mismatch repair system, where microsatellites accumulate insertions/deletions. This phenotype has been extensively characterized in colorectal cancer and is also sought in the context of Lynch syndrome diagnosis. It has recently been described in dozens of cancer types from whole genome/exome sequencing data, bearing some prognostic information. Moreover, MSI has also proven to be a major predicator of the response to immune checkpoint blockade therapy in solid cancer patients. Among the different methods developed for MSI detection in cancer, next-generation sequencing (NGS) is a promising and versatile technology offering many possibilities and advantages in diverse clinical applications compared to the gold standard PCR and capillary electrophoresis approach. NGS could notably increase the number of analyzed microsatellites and potentially be used to analyze other genetic alterations required for precision oncology. However, it requires the development of robust new computational algorithms for the analysis of NGS microsatellite data. In this chapter, we describe the different approaches developed for the assessment of MSI from NGS data in cancer, including the different microsatellite panels and computational algorithms proposed, highlighting their advantages and drawbacks, and their evaluation in different clinical applications.
Subject(s)
Colorectal Neoplasms , Neoplasms , Colorectal Neoplasms/drug therapy , Colorectal Neoplasms/genetics , DNA Mismatch Repair , High-Throughput Nucleotide Sequencing/methods , Humans , Microsatellite Instability , Microsatellite Repeats/genetics , Neoplasms/diagnosis , Neoplasms/drug therapy , Neoplasms/genetics , Precision MedicineABSTRACT
Microsatellites are polymorphic short tandem repeats of 1-6 nucleotides ubiquitously present in the genome that are extensively used in living organisms as genetic markers and in oncology to detect microsatellite instability (MSI). While the standard analysis method of microsatellites is based on PCR followed by capillary electrophoresis, it generates undesirable frameshift products known as 'stutter peaks' caused by the polymerase slippage that can greatly complicate the analysis and interpretation of the data. Here we present an easy multiplexable approach replacing PCR that is based on low temperature isothermal amplification using recombinase polymerase amplification (LT-RPA) that drastically reduces and sometimes completely abolishes the formation of stutter artifacts, thus greatly simplifying the calling of the alleles. Using HT17, a mononucleotide DNA repeat that was previously proposed as an optimal marker to detect MSI in tumor DNA, we showed that LT-RPA improves the limit of detection of MSI compared to PCR up to four times, notably for small deletions, and simplifies the identification of the mutant alleles. It was successfully applied to clinical colorectal cancer samples and enabled detection of MSI. This easy-to-handle, rapid and cost-effective approach may deeply improve the analysis of microsatellites in several biological and clinical applications.
Subject(s)
Biomarkers, Tumor/genetics , Colorectal Neoplasms , DNA/genetics , Microsatellite Instability , Microsatellite Repeats/genetics , Nucleic Acid Amplification Techniques/methods , Cell Line, Tumor , Colorectal Neoplasms/diagnosis , Colorectal Neoplasms/genetics , Humans , TemperatureABSTRACT
Summary: Cancer genomes are altered by various mutational processes and, like palimpsests, bear the signatures of these different processes. The Palimpsest R package provides a complete workflow for the characterization and visualization of mutational signatures and their evolution along tumor development. The package covers a wide range of functions for extracting both base substitution and structural variant signatures, inferring the clonality of each alteration and analyzing the evolution of mutational processes between early clonal and late subclonal events. Palimpsest also estimates the probability of each mutation being due to each process to predict the mechanisms at the origin of driver events. Palimpsest is an easy-to-use toolset for reconstructing the natural history of a tumor using whole exome or whole genome sequencing data. Availability and implementation: Palimpsest is freely available at www.github.com/FunGEST/Palimpsest. Supplementary information: Supplementary data are available at Bioinformatics online.
Subject(s)
Evolution, Molecular , Mutation , Neoplasms/genetics , Exome , Humans , SoftwareABSTRACT
OBJECTIVE: MicroRNAs (miRNAs) play an important role in the pathogenesis of autoimmune diseases such as primary Sjögren's syndrome (pSS). This study is the first to investigate miRNA expression patterns in purified T and B lymphocytes from patients with pSS using a high-throughput quantitative PCR (qPCR) approach. METHODS: Two independent cohorts of both patients with pSS and controls, one for discovery and one for replication, were included in this study. CD4+ T cells and CD19+ B cells were isolated from peripheral blood mononuclear cells by magnetic microbeads and expression of miRNAs was profiled using the Exiqon Human miRNome panel I analysing 372 miRNAs. A selection of differentially expressed miRNAs was replicated in the second cohort using specific qPCR assays. RESULTS: A major difference in miRNA expression patterns was observed between the lymphocyte populations from patients with pSS and controls. In CD4 T lymphocytes, hsa-let-7d-3p, hsa-miR-155-5 p, hsa-miR-222-3 p, hsa-miR-30c-5p, hsa-miR-146a-5p, hsa-miR-378a-3p and hsa-miR-28-5 p were significantly differentially expressed in both the discovery and the replication cohort. In B lymphocytes, hsa-miR-378a-3p, hsa-miR-222-3 p, hsa-miR-26a-5p, hsa-miR-30b-5p and hsa-miR-19b-3p were significantly differentially expressed. Potential target mRNAs were enriched in disease relevant pathways. Expression of B-cell activating factor (BAFF) mRNA was inversely correlated with the expression of hsa-miR-30b-5p in B lymphocytes from patients with pSS and functional experiments showed increased expression of BAFF after inhibiting hsa-miR-30b-5p. CONCLUSIONS: This study demonstrates major miRNAs deregulation in T and B cells from patients with pSS in two independent cohorts, which might target genes known to be involved in the pathogenesis of pSS.
Subject(s)
B-Lymphocytes/metabolism , CD4-Positive T-Lymphocytes/metabolism , Gene Expression Regulation , MicroRNAs/genetics , Sjogren's Syndrome/genetics , Aged , B-Cell Activating Factor , Case-Control Studies , Cohort Studies , Female , Humans , Leukocytes, Mononuclear/metabolism , Male , Middle Aged , Real-Time Polymerase Chain ReactionSubject(s)
Adenoma, Liver Cell/complications , Amyloidosis/etiology , Interleukin-6/metabolism , Liver Neoplasms/complications , Liver/metabolism , Serum Amyloid A Protein/metabolism , Adenoma, Liver Cell/metabolism , Amyloidosis/diagnosis , Fatal Outcome , Female , Gene Expression , Humans , Interleukin-6/genetics , Liver/cytology , Liver/pathology , Liver Neoplasms/metabolism , Middle Aged , Sequence Analysis, RNAABSTRACT
INTRODUCTION: We investigated the effect of genetic variation on gene expression in blood from a cohort of BC survivors. Further, we investigated the associations that were specific for BC survivors by performing identical analyses for a group of healthy women and comparing the results. METHODS: eQTL analysis was performed for 288 BC survivors (full data set). Further, using a subset of the data, eQTL analyses were performed on 288 BC survivors and on 81 healthy women separately and results were compared. RESULTS: A large number of associations were observed for the BC survivors, and the expression of human leukocyte antigen genes was found associated with SNPs in 100 genes. The comparison analyses with healthy women revealed associations occurring specifically in BC survivors, and the genes showed enrichment for immune system processes. CONCLUSIONS: The results suggest that the immune system has a different constitution in BC survivors compared to healthy women.
Subject(s)
Breast Neoplasms/genetics , Gene Expression , Genes, MHC Class II , Genes, MHC Class I , Genome-Wide Association Study , Polymorphism, Single Nucleotide , Survivors , Case-Control Studies , Chromosome Mapping , Cohort Studies , Female , Genetic Predisposition to Disease , Genetic Variation , Humans , Linear Models , Middle AgedABSTRACT
BACKGROUND: Microsatellite instability (MSI) due to mismatch repair deficiency (dMMR) is common in colorectal cancer (CRC). These cancers are associated with somatic coding events, but the noncoding pathophysiological impact of this genomic instability is yet poorly understood. Here, we perform an analysis of coding and noncoding MSI events at the different steps of colorectal tumorigenesis using whole exome sequencing and search for associated splicing events via RNA sequencing at the bulk-tumor and single-cell levels. RESULTS: Our results demonstrate that MSI leads to hundreds of noncoding DNA mutations, notably at polypyrimidine U2AF RNA-binding sites which are endowed with cis-activity in splicing, while higher frequency of exon skipping events are observed in the mRNAs of MSI compared to non-MSI CRC. At the DNA level, these noncoding MSI mutations occur very early prior to cell transformation in the dMMR colonic crypt, accounting for only a fraction of the exon skipping in MSI CRC. At the RNA level, the aberrant exon skipping signature is likely to impair colonic cell differentiation in MSI CRC affecting the expression of alternative exons encoding protein isoforms governing cell fate, while also targeting constitutive exons, making dMMR cells immunogenic in early stage before the onset of coding mutations. This signature is characterized by its similarity to the oncogenic U2AF1-S34F splicing mutation observed in several other non-MSI cancer. CONCLUSIONS: Overall, these findings provide evidence that a very early RNA splicing signature partly driven by MSI impairs cell differentiation and promotes MSI CRC initiation, far before coding mutations which accumulate later during MSI tumorigenesis.
Subject(s)
Alternative Splicing , Colorectal Neoplasms , Microsatellite Instability , Splicing Factor U2AF , Colorectal Neoplasms/genetics , Humans , Splicing Factor U2AF/genetics , Splicing Factor U2AF/metabolism , Mutation , Binding Sites , ExonsABSTRACT
Microsatellites are short tandem repeats of one to six nucleotides that are highly polymorphic and extensively used as genetic markers in numerous biomedical applications, including the detection of microsatellite instability (MSI) in cancer. The standard analytical method for microsatellite analysis relies on PCR amplification followed by capillary electrophoresis or, more recently, next-generation sequencing (NGS). However, their amplification during PCR generates undesirable frameshift products known as stutter peaks caused by polymerase slippage, complicating data analysis and interpretation, while very few alternative methods for microsatellite amplification have been developed to reduce the formation of these artifacts. In this context, the recently developed low-temperature recombinase polymerase amplification (LT-RPA) is an isothermal DNA amplification method at low temperature (32 °C) that drastically reduces and sometimes completely abolishes the formation of stutter peaks. LT-RPA greatly simplifies the genotyping of microsatellites and improves the detection of MSI in cancer. In this chapter, we describe in detail all the experimental steps necessary for the development of LT-RPA simplex and multiplex assays for microsatellite genotyping and MSI detection, including the design, optimization, and validation of the assays combined with capillary electrophoresis or NGS.
Subject(s)
Microsatellite Instability , Neoplasms , Humans , Recombinases/genetics , Genotype , Microsatellite Repeats , DNA/genetics , Nucleotidyltransferases , Neoplasms/geneticsABSTRACT
The choice of the best probabilistic postoperative antibiotics in bone and joint infections (BJIs) is still challenging. Since the implementation of protocolized postoperative linezolid in six French referral centers, linezolid-resistant multidrug-resistant Staphylococcus epidermidis (LR-MDRSE) strains were isolated in patients with BJI. We aimed here to describe clinical, microbiological, and molecular patterns associated with these strains. All patients with at least one intraoperative specimen positive for LR-MDRSE between 2015 and 2020 were included in this retrospective multicenter study. Clinical presentation, management, and outcome were described. LR-MDRSE strains were investigated by MIC determination for linezolid and other anti-MRSA antibiotics, characterization of genetic determinants of resistance, and phylogenetic analysis. Forty-six patients (colonization n = 10, infection n = 36) were included in five centers, 45 had prior exposure to linezolid, 33 had foreign devices. Clinical success was achieved for 26/36 patients. Incidence of LR-MDRSE increased over the study period. One hundred percent of the strains were resistant to oxazolidinones, gentamicin, clindamycin, ofloxacin, rifampicin, ceftaroline, and ceftobiprole, and susceptible to cyclins, daptomycin, and dalbavancin. Susceptibility to delafloxacin was bimodal. Molecular analysis was performed for 44 strains, and the main mutation conferring linezolid resistance was the 23S rRNA G2576T mutation. All strains belonged to the sequence type ST2 or its clonal complex, and phylogenetic analysis showed emergence of five populations corresponding geographically to the centers. We showed the emergence of new clonal populations of highly linezolid-resistant S. epidermidis in BJIs. Identifying patients at risk for LR-MDRSE acquisition and proposing alternatives to systematic postoperative linezolid use are essential. IMPORTANCE The manuscript describes the emergence of clonal linezolid-resistant strains of Staphylococcus epidermidis (LR-MDRSE) isolated from patients presenting with bone and joint infections. Incidence of LR-MDRSE increased over the study period. All strains were highly resistant to oxazolidinones, gentamicin, clindamycin, ofloxacin, rifampicin, ceftaroline, and ceftobiprole, but were susceptible to cyclins, daptomycin, and dalbavancin. Susceptibility to delafloxacin was bimodal. The main mutation conferring linezolid resistance was the 23S rRNA G2576T mutation. All strains belonged to the sequence type ST2 or its clonal complex, and phylogenetic analysis showed emergence of five populations corresponding geographically to the centers. LR-MDRSE bone and joint infections seem to be accompanied by an overall poor prognosis related to comorbidities and therapeutic issues. Identifying patients at risk for LR-MDRSE acquisition and proposing alternatives to systematic postoperative linezolid use become essential, with a preference for parenteral drugs such as lipopeptids or lipoglycopeptids.
Subject(s)
Daptomycin , Methicillin-Resistant Staphylococcus aureus , Oxazolidinones , Staphylococcal Infections , Humans , Linezolid/pharmacology , Linezolid/therapeutic use , Staphylococcus epidermidis/genetics , Rifampin/therapeutic use , Clindamycin/therapeutic use , RNA, Ribosomal, 23S/genetics , Phylogeny , Interleukin-1 Receptor-Like 1 Protein/genetics , Staphylococcal Infections/drug therapy , Staphylococcal Infections/epidemiology , Staphylococcal Infections/microbiology , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/therapeutic use , Gentamicins/therapeutic use , Ofloxacin , Microbial Sensitivity Tests , Drug Resistance, Bacterial/genetics , CeftarolineABSTRACT
The bevacizumab (bev)/olaparib (ola) maintenance regimen was approved for BRCA1/2-mutated (BRCAmut) and Homologous Recombination Deficient (HRD) high-grade Advanced Ovarian Cancer (AOC) first line setting, based on a significantly improved progression-free survival (PFS) compared to bev alone in the PAOLA-1/ENGOT-ov25 trial (NCT02477644), where HRD was detected by MyChoice CDx PLUS test. The academic shallowHRDv2 test was developed based on shallow whole-genome sequencing as an alternative to MyChoice. Analytical and clinical validities of shallowHRDv2 as compared to MyChoice on 449 PAOLA-1 tumor samples are presented. The overall agreement between shallowHRDv2 and MyChoice was 94% (369/394). Less non-contributive tests were observed with shallowHRDv2 (15/449; 3%) than with MyChoice (51/449; 11%). Patients with HRD tumors according to shallowHRDv2 (including BRCAmut) showed a significantly prolonged PFS with bev+ola versus bev (median PFS: 65.7 versus 20.3 months, hazard ratio (HR): 0.36 [95% CI: 0.24-0.53]). This benefit was significant also for BRCA1/2 wild-type tumors (40.8 versus 19.5 months, HR: 0.45 [95% CI: 0.26-0.76]). ShallowHRDv2 is a performant, clinically validated, and cost-effective test for HRD detection.
Subject(s)
Neoplasms , Ovarian Neoplasms , Humans , Female , BRCA1 Protein/genetics , BRCA2 Protein/genetics , Homologous Recombination/genetics , Ovarian Neoplasms/diagnosis , Ovarian Neoplasms/drug therapy , Ovarian Neoplasms/geneticsABSTRACT
Rheumatoid arthritis (RA) is a common systemic autoimmune disease and its onset and prognosis are controlled by genetic, immunological, and environmental factors. The HLA locus, particularly HLA-DRB1, is its strongest genetic risk determinant across ethnicities. Several other genes, including PTPN22 and PADI4, show modest association with RA. However, they cover only a part of its genetic components and their relative contribution is different between populations. To identify novel genetic determinants, we took a candidate gene approach in a trans-ethnic manner. After critical selection of 169 genes based on their immunological function, we performed SNP discovery of these genes by the resequencing of exons and surrounding areas using European and Japanese DNAs. We then generated a panel of 1,509 SNPs for case-control association study in both populations. The DerSimonian-Laird test for meta-analysis, using the combined results of the two populations, identified rs7551957 at the 5'-flanking region of the low-affinity Fc-gamma receptor IIa (FCGR2A) gene as the strongest candidate for the association (p = 8.6 × 10(-5), odds ratio = 1.58 with 95%CI 1.25-1.99). Suggestive signals were also obtained for three SNPs in the dihydropyrimidine dehydrogenase (DPYD) gene (rs6685859; p = 1.3 × 10(-4), rs7550959; p = 1.5 × 10(-4) and rs7531138; p = 1.7 × 10(-4)) and an intronic SNP, rs2269310, of the erythrocytic spectrin beta (SPTB) gene (p = 7.9 × 10(-4)).
Subject(s)
Arthritis, Rheumatoid/genetics , Genetic Predisposition to Disease/genetics , Receptors, IgG/genetics , Arthritis, Rheumatoid/ethnology , Asian People , Genetic Predisposition to Disease/epidemiology , Genetic Variation , Genotype , Humans , Japan/epidemiology , Polymorphism, Single Nucleotide , Risk Factors , White PeopleABSTRACT
Oncogene activation leads to replication stress and promotes genomic instability. Here we combine optical mapping and whole-genome sequencing (WGS) to explore in depth the nature of structural variants (SV) induced by replication stress in cyclin-activated hepatocellular carcinomas (CCN-HCC). In addition to classical tandem duplications, CCN-HCC displayed frequent intra-chromosomal and interchromosomal templated insertion cycles (TIC), likely resulting from template switching events. Template switching preferentially involves active topologically associated domains that are proximal to one another within the 3D genome. Template sizes depend on the type of cyclin activation and are coordinated within each TIC. Replication stress induced continuous accumulation of SVs during CCN-HCC progression, fostering the acquisition of new driver alterations and large-scale copy-number changes at TIC borders. Together, this analysis sheds light on the mechanisms, dynamics, and consequences of SV accumulation in tumors with oncogene-induced replication stress. SIGNIFICANCE: Optical mapping and whole-genome sequencing integration unravels a unique signature of replication stress-induced structural variants that drive genomic evolution and the acquisition of driver events in CCN-HCC.
Subject(s)
Carcinoma, Hepatocellular , Liver Neoplasms , Carcinoma, Hepatocellular/genetics , Carcinoma, Hepatocellular/pathology , Cyclins , Humans , Liver Neoplasms/genetics , Liver Neoplasms/pathology , Oncogenes , Whole Genome SequencingABSTRACT
The use of conventional methods (immunohistochemistry, pentaplex PCR) for detecting microsatellite instability (MSI), a predictive biomarker of immunotherapy efficacy, is debated for cancers with low MSI prevalence, such as breast cancer (BC). We developed two multiplex drop-off droplet digital PCR (ddPCR) assays targeting four microsatellites, initially identified from public BC whole-genome sequencing dataset. Performances of the assays were investigated and 352 tumor DNA and 28 circulating cell-free DNA from BC patients, with unknown MSI status were blindly screened. Cross-validation of ddPCR MSI status with other MSI detection methods was performed. We then monitored circulating tumor DNA (ctDNA) dynamics before and during pembrolizumab immunotherapy in one patient with MSI-high (MSI-H) metastatic BC. The assays showed high analytical specificity and sensitivity (limit of detection = 0.16%). Among N = 380 samples, seven (1.8%) were found as MSI-H by ddPCR with six of them confirmed by next-generation sequencing (NGS). Specificity was 100% in N = 133 microsatellite stable BC submitted to NGS. In the patient with MSI-H metastatic BC, ctDNA monitoring revealed an early decrease of microsatellite mutant allelic frequencies during immunotherapy. These results demonstrated MSI detection by ddPCR, a non-invasive, fast and cost-effective approach, allowing for large pre-screening of BC patients who may benefit from immunotherapy.
Subject(s)
Breast Neoplasms , Circulating Tumor DNA , Colorectal Neoplasms , Humans , Female , Microsatellite Instability , Breast Neoplasms/diagnosis , Breast Neoplasms/genetics , Circulating Tumor DNA/genetics , High-Throughput Nucleotide Sequencing/methods , Polymerase Chain Reaction , Colorectal Neoplasms/geneticsABSTRACT
Retinoblastoma is a malignant tumor of the infant retina. Nearly half of patients are predisposed to retinoblastoma by a germline RB1 pathogenic variant. Nonhereditary retinoblastoma is mainly caused by inactivation of both RB1 alleles at a somatic level. Several polymorphisms have been reported as biomarkers of retinoblastoma risk, aggressiveness, or invasion. The most informative genetic testing is obtained from tumor DNA. Historically, access to tumor DNA has been warranted by the frequent indication of enucleation, which has decreased because of advances in conservative approaches. Recent studies showed that tumor cell-free DNA can be analyzed in aqueous humor from retinoblastoma patients. This report describes a next-generation sequencing method relying on unique molecular identifiers for a highly sensitive detection of retinoblastoma genetic predisposition and biomarkers in a single analysis. It is the first use of unique molecular identifiers for retinoblastoma genetics. This gene panel enables the detection of RB1 point variants, large genome rearrangements, and loss of heterozygosity. It is adapted for genomic DNA extracted from blood or tumor DNA extracted from tumor fragment, aqueous humor, or plasma. The access to tumor cell-free DNA improves the diagnosis of genetic predisposition in case of conservative ocular therapy and provides access to biomarkers guiding the treatment strategy. The analysis of a gene panel is cost-effective and can be easily implemented in diagnostic laboratories.
Subject(s)
Biomarkers, Tumor/genetics , Retinal Neoplasms/genetics , Retinoblastoma/genetics , Aqueous Humor/physiology , Biomarkers, Tumor/blood , Child , Child, Preschool , Female , Genetic Predisposition to Disease , High-Throughput Nucleotide Sequencing , Humans , Infant , Loss of Heterozygosity , Male , Polymorphism, Single Nucleotide , Retinoblastoma Binding Proteins/genetics , Ubiquitin-Protein Ligases/geneticsABSTRACT
Pediatric liver cancers (PLC) comprise diverse diseases affecting infants, children, and adolescents. Despite overall good prognosis, PLCs display heterogeneous response to chemotherapy. Integrated genomic analysis of 126 pediatric liver tumors showed a continuum of driver mechanisms associated with patient age, including new targetable oncogenes. In 10% of patients with hepatoblastoma, all before three years old, we identified a mosaic premalignant clonal expansion of cells altered at the 11p15.5 locus. Analysis of spatial and longitudinal heterogeneity revealed an important plasticity between "hepatocytic," "liver progenitor," and "mesenchymal" molecular subgroups of hepatoblastoma. We showed that during chemotherapy, "liver progenitor" cells accumulated massive loads of cisplatin-induced mutations with a specific mutational signature, leading to the development of heavily mutated relapses and metastases. Drug screening in PLC cell lines identified promising targets for cisplatin-resistant progenitor cells, validated in mouse xenograft experiments. These data provide new insights into cisplatin resistance mechanisms in PLC and suggest alternative therapies. SIGNIFICANCE: PLCs are deadly when they resist chemotherapy, with limited alternative treatment options. Using a multiomics approach, we identified PLC driver genes and the cellular phenotype at the origin of cisplatin resistance. We validated new treatments targeting these molecular features in cell lines and xenografts.This article is highlighted in the In This Issue feature, p. 2355.
Subject(s)
Antineoplastic Agents/therapeutic use , Cisplatin/therapeutic use , Drug Resistance, Neoplasm/genetics , Liver Neoplasms/drug therapy , Adolescent , Carcinoma, Hepatocellular/drug therapy , Carcinoma, Hepatocellular/genetics , Child , Child, Preschool , Female , Gene Expression Profiling , Genomics , Hepatoblastoma/drug therapy , Hepatoblastoma/genetics , Humans , Infant , Liver Neoplasms/genetics , Male , Neoplasm Recurrence, Local , PhenotypeABSTRACT
PURPOSE: The analysis of circulating tumor DNA (ctDNA), a fraction of total cell-free DNA (cfDNA), might be of special interest in retinoblastoma patients. Because the accessibility to tumor tissue is very limited in these patients, either for histopathological diagnosis of suspicious intraocular masses (biopsies are proscribed) or for somatic RB1 studies and genetic counseling (due to current successful conservative approaches), we aim to validate the detection of ctDNA in plasma of non-hereditary retinoblastoma patients by molecular analysis of RB1 gene. EXPERIMENTAL DESIGN: In a cohort of 19 intraocular unilateral non-hereditary retinoblastoma patients for whom a plasma sample was available at diagnosis, we performed high-deep next-generation sequencing (NGS) of RB1 in cfDNA. Two different bioinformatics/statistics approaches were applied depending on whether the somatic RB1 status was available or not. RESULTS: Median plasma sample volume was 600 µL [100-1000]; median cfDNA plasma concentration was 119 [38-1980] and 27 [11-653] ng/mL at diagnosis and after complete remission, respectively. In the subgroup of patients with known somatic RB1 alterations (n = 11), seven of nine somatic mutations were detected (median allele fraction: 6.7%). In patients without identified somatic RB1 alterations (n = 8), six candidate variants were identified for seven patients. CONCLUSIONS: Despite small tumor size, blood-ocular barrier, poor ctDNA blood release and limited plasma sample volumes, we confirm that it is possible to detect ctDNA with high-deep NGS in plasma from patients with intraocular non-hereditary retinoblastoma. This may aid in diagnosis of suspicious cases, family genetic counseling or follow-up of residual intraocular disease.