BACKGROUND: Evolution of indolent to aggressive lymphoma has been described in dogs but is difficult to distinguish from the de novo development of a second, clonally distinct lymphoma. Differentiation of these scenarios can be aided by next generation sequencing (NGS)-based assessment of clonality of lymphocyte antigen receptor genes. CASE PRESENTATION: An 8-year-old male intact Mastiff presented with generalized lymphadenomegaly was diagnosed with nodal T zone lymphoma (TZL) based on cytology, histopathology, immunohistochemistry and flow cytometry. Thirteen months later, the dog re-presented with progressive lymphadenomegaly, and based on cytology and flow cytometry, a large B cell lymphoma (LBCL) was diagnosed. Sequencing-based clonality testing confirmed the de novo development of a LBCL and the persistence of a TZL. CONCLUSIONS: The occurrence of two distinct lymphoid neoplasms should be considered if patient features and tumor cytomorphology or immunophenotype differ among sequential samples. Sequencing-based clonality testing may provide conclusive evidence of two concurrent and distinct clonal lymphocyte populations, termed most appropriately "composite lymphoma".

• Klíčová slova
• Antigen receptor gene rearrangement, Canine, Clonality, Composite lymphoma, Dog, Lymphoma, Lymphosarcoma, PARR,
• MeSH
• alkylační protinádorové látky aplikace a dávkování   terapeutické užití   MeSH
• chlorambucil aplikace a dávkování   terapeutické užití   MeSH
• difúzní velkobuněčný B-lymfom komplikace   patologie   veterinární   MeSH
• hormonální protinádorové látky aplikace a dávkování   terapeutické užití   MeSH
• lymfom T-buněčný komplikace   patologie   veterinární   MeSH
• nemoci psů patologie   MeSH
• prednison aplikace a dávkování   terapeutické užití   MeSH
• psi MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• psi MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH
• Názvy látek
• alkylační protinádorové látky MeSH
• chlorambucil MeSH
• hormonální protinádorové látky MeSH
• prednison MeSH

Amplicon-based next-generation sequencing (NGS) of immunoglobulin (IG) and T-cell receptor (TR) gene rearrangements for clonality assessment, marker identification and quantification of minimal residual disease (MRD) in lymphoid neoplasms has been the focus of intense research, development and application. However, standardization and validation in a scientifically controlled multicentre setting is still lacking. Therefore, IG/TR assay development and design, including bioinformatics, was performed within the EuroClonality-NGS working group and validated for MRD marker identification in acute lymphoblastic leukaemia (ALL). Five EuroMRD ALL reference laboratories performed IG/TR NGS in 50 diagnostic ALL samples, and compared results with those generated through routine IG/TR Sanger sequencing. A central polytarget quality control (cPT-QC) was used to monitor primer performance, and a central in-tube quality control (cIT-QC) was spiked into each sample as a library-specific quality control and calibrator. NGS identified 259 (average 5.2/sample, range 0-14) clonal sequences vs. Sanger-sequencing 248 (average 5.0/sample, range 0-14). NGS primers covered possible IG/TR rearrangement types more completely compared with local multiplex PCR sets and enabled sequencing of bi-allelic rearrangements and weak PCR products. The cPT-QC showed high reproducibility across all laboratories. These validated and reproducible quality-controlled EuroClonality-NGS assays can be used for standardized NGS-based identification of IG/TR markers in lymphoid malignancies.

• MeSH
• akutní lymfatická leukemie genetika   MeSH
• genetické markery genetika   MeSH
• genová přestavba T-lymfocytů genetika   MeSH
• geny pro imunoglobuliny genetika   MeSH
• geny TcR genetika   MeSH
• imunoglobuliny genetika   MeSH
• lidé MeSH
• receptory antigenů T-buněk genetika   MeSH
• referenční standardy MeSH
• rekombinace genetická genetika   MeSH
• reprodukovatelnost výsledků MeSH
• reziduální nádor genetika   MeSH
• výpočetní biologie metody   MeSH
• vysoce účinné nukleotidové sekvenování metody   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• genetické markery MeSH
• imunoglobuliny MeSH
• receptory antigenů T-buněk MeSH

Assessment of clonality, marker identification and measurement of minimal residual disease (MRD) of immunoglobulin (IG) and T cell receptor (TR) gene rearrangements in lymphoid neoplasms using next-generation sequencing (NGS) is currently under intensive development for use in clinical diagnostics. So far, however, there is a lack of suitable quality control (QC) options with regard to standardisation and quality metrics to ensure robust clinical application of such approaches. The EuroClonality-NGS Working Group has therefore established two types of QCs to accompany the NGS-based IG/TR assays. First, a central polytarget QC (cPT-QC) is used to monitor the primer performance of each of the EuroClonality multiplex NGS assays; second, a standardised human cell line-based DNA control is spiked into each patient DNA sample to work as a central in-tube QC and calibrator for MRD quantification (cIT-QC). Having integrated those two reference standards in the ARResT/Interrogate bioinformatic platform, EuroClonality-NGS provides a complete protocol for standardised IG/TR gene rearrangement analysis by NGS with high reproducibility, accuracy and precision for valid marker identification and quantification in diagnostics of lymphoid malignancies.

• MeSH
• genetické markery genetika   MeSH
• genová přestavba genetika   MeSH
• imunoglobuliny genetika   MeSH
• lidé MeSH
• receptory antigenů T-buněk genetika   MeSH
• reprodukovatelnost výsledků MeSH
• reziduální nádor genetika   MeSH
• řízení kvality MeSH
• výpočetní biologie metody   MeSH
• vysoce účinné nukleotidové sekvenování metody   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• genetické markery MeSH
• imunoglobuliny MeSH
• receptory antigenů T-buněk MeSH

Minimal residual disease (MRD) is the most important independent prognostic factor in acute lymphoblastic leukemia (ALL). Since it has been implemented into in treatment stratification strategies, cure rates have improved significantly for all age groups. Real time quantitative (RQ)-PCR of clonal immunoglobulin and T-cell receptor gene rearrangements using allele-specific primers is currently regarded as the gold standard for MRD analysis in ALL, as it is not only highly sensitive and specific but also provides accurate MRD quantification. Following recent advances in next-generation sequencing (NGS), much attention has been devoted to the development of NGS-based MRD assays. This new technique can enhance sensitivity provided that sufficient numbers of cells are analyzed. Recent reports have shown that NGS-MRD also tends to be more specific for relapse prediction than RQ-PCR. In addition, NGS provides information on the physiological B- and T-cell repertoire during and after treatment, which has been shown to be prognostically relevant. However, before implementation of NGS-MRD detection in clinical practice, several issues must be addressed and the whole workflow needs to be standardized, including not only the analytical phase (spike-in calibrators, quality controls) but also the pre-analytical (e.g. sample preparation) and the post-analytical phases (e.g. bioinformatics pipeline, guidelines for correct data interpretation). These topics are currently addressed by a European network, the EuroClonality-NGS Consortium. In conclusion, NGS is a promising tool for MRD detection with the potential to overcome most of the limitations of RQ-PCR and to become the new gold standard for MRD detection in ALL.

• Klíčová slova
• Acute Lymphoblastic Leukemia, Marker Identification, Minimal Residual Disease, Minimal Residual Disease Detection, Multicolor Flow Cytometry,
• MeSH
• akutní lymfatická leukemie genetika   MeSH
• lidé MeSH
• prognóza MeSH
• receptory antigenů T-buněk genetika   MeSH
• reziduální nádor MeSH
• sekvenční analýza DNA metody   MeSH
• vysoce účinné nukleotidové sekvenování metody   MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• receptory antigenů T-buněk MeSH