How molecular advances may improve the diagnosis and management of PTCL patients

Peripheral T-cell lymphomas (PTCL) comprised more than 30 rare heterogeneous entities, representing 10 to 15% of adult non-Hodgkin lymphomas. Although their diagnosis is still mainly based on clinical, pathological, and phenotypic features, molecular studies have allowed for a better understanding of the oncogenic mechanisms involved and the refinement of many PTCL entities in the recently updated classifications. The prognosis remains poor for most entities (5-year overall survival < 30%), with current conventional therapies based on anthracyclin-based polychemotherapy regimen, despite many years of clinical trials. The recent use of new targeted therapies appears to be promising for relapsed/refractory patients, such as demethylating agents in T-follicular helper (TFH) PTCL. However further studies are needed to evaluate the proper combination of these drugs in the setting of front-line therapy. In this review, we will summarize the oncogenic events for the main PTCL entities and report the molecular targets that have led to the development of new therapies. We will also discuss the development of innovative high throughput technologies that aid the routine workflow for the histopathological diagnosis and management of PTCL patients

Molecular subgroups among peripheral T-cell lymphomas

Les lymphomes T périphériques (PTCL) sont des tumeurs rares et de mauvais pronostic, regroupant une trentaine d’entités hétérogènes dans la classification OMS ; les plus fréquentes sont représentées par le groupe des lymphomes T de phénotype TFH, le lymphome T non spécifié (PTCL-NOS), et les lymphomes T à grandes cellules anaplasiques (ALCL) avec ou sans réarrangement du gène ALK. Compte-tenu de leur rareté, de leur hétérogénéité et de la complexité de la classification de ces tumeurs, leur diagnostic n’est pas toujours aisé et résulte d’une confrontation des données histopathologiques, moléculaires et cytogénétiques. De plus, certaines entités demeurent hétérogènes sur le plan morphologique et/ou moléculaire, notamment les PTCL-NOS et les ALCL ALK-. Une meilleure définition de ces entités hétérogènes contribuerait à l’amélioration de leur prise en charge diagnostique, pronostique et thérapeutique. Nous avons tout d’abord développé un outil moléculaire d’expression génique par RT-MLPA, en ciblant 21 gènes pertinents pour la classification des principales entités de lymphome T périphérique, et pouvant facilement être intégré dans le diagnostic de routine. Notre outil a permis de classer en accord avec le diagnostic histopathologique, 91% des cas correspondant aux entités « définies » de la classification OMS, et a proposé une classe diagnostique pour 91% des cas de PTCL-NOS. La robustesse de cet outil a été évaluée par une étude multicentrique sur une série indépendante, avec une concordance de classification pour 90% des échantillons. Afin de compléter cette démarche de caractérisation moléculaire, nous avons également développé une technologie innovante de RT-PCR dépendante de la ligation, pour la détection de 33 transcrits de fusion. Nous avons détecté des transcrits de fusions dans 15.3% (39/255) des échantillons, et dans 13.6% des lymphomes non ALCL ALK+, notamment les PTCL de phénotype TFH. Enfin, nous avons réalisé une analyse intégrative associant séquençage complet exomique, séquençage de l’ARN et étude de la méthylation de l’ADN, afin de mieux caractériser les deux entités hétérogènes (PTCL-NOS et ALCL ALK-), et d’identifier des marqueurs ayant un potentiel impact diagnostique, pronostique ou thérapeutique. Nos analyses préliminaires nous ont permis de retrouver un sous-groupe constitué d’ALCL ALK- ayant un réarrangement du locus DUSP22/IRF4, caractérisé par des profils de méthylation, d’expression et mutationnel particulièrement homogènes. Au sein des PTCL-NOS, les analyses préliminaires suggèrent la grande hétérogénéité moléculaire de cette catégorie et plusieurs gènes candidats potentiellement impliqués dans l’oncogenèse du sous-groupe de phénotype cytotoxique devront être validés. Les données de méthylation montrent également deux sous-groupes au sein des PTCL de phénotype TFH, dont la signification reste à déterminer. Ces résultats préliminaires devront être validés puis complétés par une analyse intégrative, pour constituer la base de travaux ultérieurs.Peripheral T-cell lymphomas (PTCL) constitute a heterogeneous group of T-cell neoplasms, comprising about 30 distinct entities according to the revised WHO classification. Most of them show a poor outcome. PTCL of TFH derivation are the most prevalent, followed by PTCL not otherwise specified (PTCL-NOS), and anaplastic large cell lymphoma (ALCL) with or without ALK rearrangement. Given the rarity and the heterogeneity of these tumors, as well as their complex classification, their diagnosis is challenging, based on histopathological, molecular, cytogenetic and clinical features. Moreover, PTCL-NOS and ALCL ALK- remain heterogeneous categories. There is a need for a better understanding of oncogenesis of these entities to improve histopathological and molecular characterization, consequently their clinical management. We first developed a multiplex gene expression profiling assay (RT-MLPA), targeting 21 genes relevant for the classification of the main PTCL entities in the routine practice. Our molecular classifier accurately classified 91% of well-defined PTCL entities according to the histopathological diagnosis, and proposed a molecular class for 91% of PTCL-NOS. To evaluate the robustness of our assay, we performed validation on an independent cohort in 3 institutions, resulting in a concordance of the molecular classification for 90% of the samples. To extend the molecular characterization of PTCL, we developed a ligation dependent RTPCR based assay for the detection of 33 transcript fusions. We detected fusion transcripts in 15.3% of the cohort (39/255), including non-ALK fusion transcripts in 13.6% of PTCL, mostly of TFH derivation. Finally, we conducted a discovery analysis of PTCLs, integrating whole exome sequencing, RNA sequencing and methyloma analysis, with the aim to improve characterization of the heterogeneous categories of PTCL-NOS and ALK-negative ALCL, and identify molecular markers of potential diagnostic, prognostic or therapeutic relevance. Our preliminary results extended the presence of a homogeneous group of ALK-negative ALCL harboring a DUSP22/IRF4 rearrangement, showing a peculiar methyloma, gene expression and mutational profile. PTCL-NOS appeared to be very heterogeneous at the molecular level, with preliminary results suggesting that oncogenesis of a subgroup with a cytotoxic phenotype may implicate candidate genes. Methylation data also identified 2 subgroups among PTCL of TFH derivation, whose relevance remains to be elucidated. The integrative analyses of these preliminary results and their validation will be the subject of future projects

Monoclonal B lymphocytosis and minimal change disease: a new monoclonal B-cell disorder of renal significance?

International audienceChronic lymphocytic leukemia (CLL) may induce renal complications, which are becoming increasingly common, but in this context the occurrence of minimal change disease (MCD) remains rare. Monoclonal B lymphocytosis (MBL) is a precursor state of CLL and is currently under recognized. Since MBL is seen as a benign disorder that rarely evolves into CLL, screening for MBL is not standardized and does not require any treatment. When reviewing renal disease associated with MBL, there is very scant data in the literature and to date there is no case describing the association between MBL and MCD. Here, we describe the case of a 71-year old woman admitted for nephrotic syndrome (NS). We diagnosed a MBL. Kidney biopsy revealed MCD. Treatment with corticosteroids was introduced but no improvement was observed. Chemotherapy with rituximab and chlorambucil was thus started, leading to complete remission of both MBL and MCD. To our knowledge, this is the first description of the association of MBL and MCD. This case suggests that screening for MBL may have unexpected diagnostic and therapeutic implications in patients presenting with seemingly idiopathic NS

Complete pathological regression of hepatocellular carcinoma with portal vein thrombosis treated with sorafenib.

International audienceSorafenib is a molecular-targeted therapy used in palliative treatment of advanced hepatocellular carcinoma (HCC) in Child-Pugh A patients. We describe the case of a patient who presented with a large HCC in the left liver associated with portal vein thrombosis (PVT). After 9 months of sorafenib treatment, reassessment showed that the tumors had decreased in size with recanalization of the portal vein. A lateral left hepatectomy was performed and pathology showed complete necrosis of the tumor. Sorafenib can downstage HCC in patients with cirrhosis allowing further surgical resection

The spectrum of kidney pathology in B-cell chronic lymphocytic leukemia / small lymphocytic lymphoma: a 25-year multicenter experience.

Chronic lymphocytic leukemia and small lymphocytic lymphoma are 2 different presentations of the most common B-cell neoplasm in western countries (CLL/SLL). In this disease, kidney involvement is usually silent, and is rarely reported in the literature. This study provides a clinicopathological analysis of all-cause kidney disease in CLL/SLL patients.Fifteen CLL/SLL patients with kidney biopsy were identified retrospectively. Demographic, clinical, pathological and laboratory data were assessed at biopsy, and during follow-up.At biopsy 11 patients presented impaired renal function, 7 patients nephrotic syndrome, 6 patients dysproteinemia, and 3 patients cryoglobulinemia. Kidney pathology revealed CLL/SLL-specific monoclonal infiltrate in 10 biopsies, glomerulopathy in 9 biopsies (5 membranoproliferative glomerulonephritis, 2 minimal change disease, 1 glomerulonephritis with organized microtubular monoclonal immunoglobulin deposits, 1 AHL amyloidosis). Five patients presented interstitial granulomas attributed to CLL/SLL. After treatment of the hematological disease, improvement of renal function was observed in 7/11 patients, and remission of nephrotic syndrome in 5/7 patients. During follow-up, aggravation of the kidney disease systematically occurred in the absence of favorable response to hematological treatment.A broad spectrum of kidney diseases is associated with CLL/SLL. In this setting, kidney biopsy can provide important information for diagnosis and therapeutic guidance

Prognostic Value of C4d Immunolabelling in Adult Patients With IgA Vasculitis

International audienceBackground and Objectives: Glomerular C4d deposits are associated the severity and outcomes of IgA nephropathy. Whether this holds true in immunoglobulin A vasculitis (IgAV) is not known. The main objective of the study was to analyze the prognostic value of glomerular C4d immunolabelling on kidney impairment in adults with IgAV. Design, Setting, Participants, Measurements: This retrospective cohort study included 120 adults with IgAV and a kidney biopsy performed between 1995 and 2018 in two French university hospital centers. All paraffin-embedded biopsies were reassessed according to Oxford classification. Immunofluorescence for C4d was performed in all cases. For analysis, patients were grouped according to positivity for C4d in the glomerular area. The main outcome was a composite endpoint of 50% increase in 24 h-proteinuria, or eGFR decrease by 50%, or kidney replacement therapy. Results: The median follow-up was 28.3 months. Twenty-three patients met the composite endpoint, 12 for kidney replacement therapy, 6 for an eGFR decrease >50% and 5 for a >50% increase in proteinuria. At time of biopsy, the median proteinuria was 1.9 g/24 h and the median eGFR 73.5 mL/min/1.73 m 2 . Among the 102 patients evaluable for C4d, 24 were positive on >30% glomeruli, mainly with a parieto-mesangial pattern. In this group, the initial proteinuria was more frequently nephrotic than in the C4d– group (60% vs. 33%, P = 0.039). Mesangial hypercellularity was more frequent in the C4d+ group (42% vs. 13%; P = 0.006) whereas macroscopic hematuria was more frequent in the C4d– group (18% vs. 0%; P = 0.03). After a median follow-up of 28 months, kidney survival did not differ according to C4d status. Conclusion: In a population of adult IgAV patients, glomerular positivity for C4d was associated with the severity of the kidney disease at presentation, but not with subsequent renal function deterioration

CLL/SLL infiltrate (case 12).

<p>(a) Masson trichrome staining. (b) Specific immunostaining to human CD3. (c) Specific immunostaining to human CD5. (d) Specific immunostaining to human CD20. Light microscopy, original magnification, X 40.</p

Representative cases of MPGN.

<p>(a) Case 10. Light microscopy, Masson trichrome staining. Cryoglobulin-related MPGN. Endocapillary proliferation, fibrinoid necrosis and pseudo-thrombi. Original magnification, X 20. (b) Case 11. Light microscopy, Masson trichrome. Endo- and extracapillary proliferation. Note the severe CLL/SLL monomorphic infiltrate. Original magnification, X 40. (c) Case 11 (IgG kappa type I cryoglobulin). Immunofluorescence microscopy. Endomembranous deposits of IgG1, kappa, C3, C1q. Original magnification, X 20. (d) Case 11. Electron microscopy. Subendothelial granular and fibrillar deposits. Bar = 1200 nm.</p

Circulating tumor DNA in primary mediastinal large B-cell lymphoma versus classical Hodgkin lymphoma: a retrospective study

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