Generation and External Validation of a Histologic Transformation Risk Model for Patients with Follicular Lymphoma.

Follicular lymphoma (FL) is the most frequent indolent lymphoma. Some patients (10%-15%) experience histologic transformation (HT) to a more aggressive lymphoma, usually diffuse large B-cell lymphoma (DLBCL). This study aimed to validate and improve a genetic risk model to predict HT at diagnosis.We collected mutational data from diagnosis biopsies of 64 FL patients. We combined them with the data from a previously published cohort (total n = 104; 62 from nontransformed and 42 from patients who did transform to DLBCL). This combined cohort was used to develop a nomogram to estimate the risk of HT. Prognostic mutated genes and clinical variables were assessed using Cox regression analysis to generate a risk model. The model was internally validated by bootstrapping and externally validated in an independent cohort. Its performance was evaluated using a concordance index and a calibration curve. The clinicogenetic nomogram included the mutational status of 3 genes (HIST1HE1, KMT2D, and TNFSR14) and high-risk Follicular Lymphoma International Prognostic Index and predicted HT with a concordance index of 0.746. Patients were classified as being at low or high risk of transformation. The probability HT function at 24 months was 0.90 in the low-risk group vs 0.51 in the high-risk group and, at 60 months, 0.71 vs 0.15, respectively. In the external validation cohort, the probability HT function in the low-risk group was 0.86 vs 0.54 in the high-risk group at 24 months, and 0.71 vs 0.32 at 60 months. The concordance index in the external cohort was 0.552. In conclusion, we propose a clinicogenetic risk model to predict FL HT to DLBLC, combining genetic alterations in HIST1H1E, KMT2D, and TNFRSF14 genes and clinical features (Follicular Lymphoma International Prognostic Index) at diagnosis. This model could improve the management of FL patients and allow treatment strategies that would prevent or delay transformation.

CD8+ NKs as a potential biomarker of complete response and survival with lenalidomide plus R-GDP in the R2-GDP-GOTEL trial in recurrent/refractory diffuse large B cell lymphoma.

Background: Diffuse large B cell lymphoma (DLBCL) is the most common non-Hodgkin lymphoma worldwide. DLBCL is an aggressive disease that can be cured with upfront standard chemoimmunotherapy schedules. However, in approximately 35-40% of the patients DLBCL relapses, and therefore, especially in this setting, the search for new prognostic and predictive biomarkers is an urgent need. Natural killer (NK) are effector cells characterized by playing an important role in antitumor immunity due to their cytotoxic capacity and a subset of circulating NK that express CD8 have a higher cytotoxic function. In this substudy of the R2-GDP-GOTEL trial, we have evaluated blood CD8+ NK cells as a predictor of treatment response and survival in relapsed/refractory (R/R) DLBCL patients. Methods: 78 patients received the R2-GDP schedule in the phase II trial. Blood samples were analyzed by flow cytometry. Statistical analyses were carried out in order to identify the prognostic potential of CD8+ NKs at baseline in R/R DLBCL patients. Results: Our results showed that the number of circulating CD8+ NKs in R/R DLBCL patients were lower than in healthy donors, and it did not change during and after treatment. Nevertheless, the level of blood CD8+ NKs at baseline was associated with complete responses in patients with R/R DLBCL. In addition, we also demonstrated that CD8+ NKs levels have potential prognostic value in terms of overall survival in R/R DLBCL patients. Conclusion: CD8+ NKs represent a new biomarker with prediction and prognosis potential to be considered in the clinical management of patients with R/R DLBCL. Clinical trial registration: https://www.clinicaltrialsregister.eu/ctr-search/search?query=2014-001620-29 EudraCT, ID:2014-001620-29.

A genetic profiling guideline to support diagnosis and clinical management of lymphomas.

The new lymphoma classifications (International Consensus Classification of Mature Lymphoid Neoplasms, and 5th World Health Organization Classification of Lymphoid Neoplasms) include genetics as an integral part of lymphoma diagnosis, allowing better lymphoma subclassification, patient risk stratification, and prediction of treatment response. Lymphomas are characterized by very few recurrent and disease-specific mutations, and most entities have a heterogenous genetic landscape with a long tail of recurrently mutated genes. Most of these occur at low frequencies, reflecting the clinical heterogeneity of lymphomas. Multiple studies have identified genetic markers that improve diagnostics and prognostication, and next-generation sequencing is becoming an essential tool in the clinical laboratory. This review provides a "next-generation sequencing" guide for lymphomas. It discusses the genetic alterations of the most frequent mature lymphoma entities with diagnostic, prognostic, and predictive potential and proposes targeted sequencing panels to detect mutations and copy-number alterations for B- and NK/T-cell lymphomas.

Genetic Alterations in Members of the Proteasome 26S Subunit, AAA-ATPase (PSMC) Gene Family in the Light of Proteasome Inhibitor Resistance in Multiple Myeloma.

For the treatment of Multiple Myeloma, proteasome inhibitors are highly efficient and widely used, but resistance is a major obstacle to successful therapy. Several underlying mechanisms have been proposed but were only reported for a minority of resistant patients. The proteasome is a large and complex machinery. Here, we focus on the AAA ATPases of the 19S proteasome regulator (PSMC1-6) and their implication in PI resistance. As an example of cancer evolution and the acquisition of resistance, we conducted an in-depth analysis of an index patient by applying FISH, WES, and immunoglobulin-rearrangement sequencing in serial samples, starting from MGUS to newly diagnosed Multiple Myeloma to a PI-resistant relapse. The WES analysis uncovered an acquired PSMC2 Y429S mutation at the relapse after intensive bortezomib-containing therapy, which was functionally confirmed to mediate PI resistance. A meta-analysis comprising 1499 newly diagnosed and 447 progressed patients revealed a total of 36 SNVs over all six PSMC genes that were structurally accumulated in regulatory sites for activity such as the ADP/ATP binding pocket. Other alterations impact the interaction between different PSMC subunits or the intrinsic conformation of an individual subunit, consequently affecting the folding and function of the complex. Interestingly, several mutations were clustered in the central channel of the ATPase ring, where the unfolded substrates enter the 20S core. Our results indicate that PSMC SNVs play a role in PI resistance in MM.

Monitoring of Circulating Tumor DNA Predicts Response to Treatment and Early Progression in Follicular Lymphoma: Results of a Prospective Pilot Study.

PURPOSE: Follicular lymphoma (FL) is the most frequent indolent non-Hodgkin lymphoma. Around 20% of patients suffer early disease progression within 24 months (POD24) of diagnosis. This study examined the significance of circulating tumor DNA (ctDNA) in predicting response to therapy and POD24 in patients with FL. EXPERIMENTAL DESIGN: We collected 100 plasma samples, before and during the treatment, from 36 patients with FL prospectively enrolled in 8 Spanish hospitals. They were treated with a chemotherapy-rituximab regimen and followed up for a median of 3.43 years. We performed targeted deep sequencing in cell-free DNA (cfDNA) and tumor genomic DNA from 31 diagnostic biopsy samples. RESULTS: Of the alterations detected in the diagnostic tissue samples, 73% (300/411) were also identified in basal cfDNA. The mean numbers of alterations per basal cfDNA sample in patients who suffered progression of disease within 24 months (POD24-pos) or did not achieve complete response (non-CR) were significantly higher than in POD24-neg or CR patients (unpaired samples t test, P = 0.0001 and 0.001, respectively). Pretreatment ctDNA levels, as haploid genome equivalents per milliliter of plasma, were higher in patients without CR (P = 0.02) and in POD24-pos patients compared with POD24-neg patients (P < 0.001). Dynamic analysis showed that ctDNA levels decreased dramatically after treatment, although the reduction was more significant in patients with CR and POD24-neg patients. CONCLUSIONS: Basal ctDNA levels are associated with the risk of early progression and response to treatment in FL. cfDNA monitoring and genotyping during treatment and follow-up predict response to treatment and early progression.

An integrated prognostic model for diffuse large B-cell lymphoma treated with immunochemotherapy.

Diffuse large B-cell lymphoma (DLBCL), the most frequent non-Hodgkin's lymphoma subtype, is characterized by strong biological, morphological, and clinical heterogeneity, but patients are treated with immunochemotherapy in a relatively homogeneous way. Here, we have used a customized NanoString platform to analyze a series of 197 homogeneously treated DLBCL cases. The platform includes the most relevant genes or signatures known to be useful for predicting response to R-CHOP (Rituximab, Cyclophosphamide, Doxorubicin, Vincristine, and Prednisone) in DLBCL cases. We generated a risk score that combines the International Prognostic Index with cell of origin and double expression of MYC/BCL2, and stratified the series into three groups, yielding hazard ratios from 0.15 to 5.49 for overall survival, and from 0.17 to 5.04 for progression-free survival. Group differences were highly significant (p < 0.0001), and the scoring system was applicable to younger patients (<60 years of age) and patients with advanced or localized stages of the disease. Results were validated in an independent dataset from 166 DLBCL patients treated in two distinct clinical trials. This risk score combines clinical and biological data in a model that can be used to integrate biological variables into the prognostic models for DLBCL cases.

Activity and safety of topical pimecrolimus in patients with early stage mycosis fungoides (PimTo-MF): a single-arm, multicentre, phase 2 trial.

BACKGROUND: The calcineurin pathway is often activated in mycosis fungoides. We aimed to assess the activity and safety of topical pimecrolimus, a calcineurin inhibitor, in patients with early mycosis fungoides. METHODS: PimTo-MF was a single-arm, multicentre, phase 2 trial done at six medical centres in Spain. Patients (aged ≥18 years) had histologically confirmed early mycosis fungoides (stages IA-IIA) and an Eastern Cooperative Oncology Group performance status of 0-1. Key exclusion criteria included the use of concurrent treatments for mycosis fungoides, including sunbathing, topical or systemic corticosteroids, and other calcineurin inhibitors. Patients applied topical pimecrolimus 1% cream on their skin lesions twice daily for 16 weeks (1 g per 2% of body surface), with subsequent follow-up of 12 months. Dosage modifications were not allowed. To evaluate adherence to the treatment, patients were instructed to return all empty tubes to the hospital (as per drug accountability protocols). The primary endpoint was the overall response ratein the intention-to-treat population. PimTo-MF is registered with EudraCT, 2014-001377-14, and is complete. FINDINGS: Between March 1, 2015, and Sept 30, 2016, 39 patients were enrolled. All patients were assessable, with a median age of 51·5 years (IQR 45-62), and the population was predominantly male (24 male [62%], 15 female [38%]). Median follow-up after baseline was 5·7 years (IQR 5·7-6·2). 22 (56%) of 39 patients had an overall response (one complete response, 21 partial responses). Responses were observed across IA (14 [54%] of 26 patients) and IB (eight [73%] of 11 patients) clinical stages, but not IIA. Topical pimecrolimus was well tolerated and no patient required a dose reduction or discontinued treatment because of unacceptable drug-related toxicity. No patients were lost to follow-up or discontinued treatment. 13 (33%) of 39 patients reported adverse events; transitory mild burning or pruritus (grade 1) was the most common, seen in eight (21%) patients. In three (8%) of these patients, the burning or pruritus was considered related to treatment. No grade 4 or 5 adverse events were observed. INTERPRETATION: Pimecrolimus 1% cream seems active and safe in patients with early stage mycosis fungoides. Our findings should be taken with caution until long-term follow-up data are obtained that confirm the safety of this treatment. Further controlled clinical trials are warranted to confirm these results. FUNDING: Instituto de Salud Carlos III and the European Regional Development Fund. TRANSLATION: For the Spanish translation of the abstract see Supplementary Materials section.

Lenalidomide plus R-GDP (R2-GDP) in Relapsed/Refractory Diffuse Large B-Cell Lymphoma: Final Results of the R2-GDP-GOTEL Trial and Immune Biomarker Subanalysis.

PURPOSE: New therapeutic options are needed in relapsed/refractory diffuse large B-cell lymphoma (R/R DLBCL). Lenalidomide-based schedules can reverse rituximab refractoriness in lymphoma. PATIENTS AND METHODS: In the phase II R2-GDP trial, 78 patients unsuitable for autologous stem cell transplant received treatment with the following schedule: lenalidomide 10 mg Days (D)1-14, rituximab 375 mg/m2 D1, cisplatin 60 mg/m2 D1, gemcitabine 750 mg/m2 D1 and D8, and dexamethasone 20 mg D1-3, up to 6 cycles (induction phase), followed by lenalidomide 10 mg (or last lenalidomide dose received) D1-21 every 28 days (maintenance phase). Primary endpoint was overall response rate (ORR). Secondary endpoints included progression-free survival (PFS), overall survival (OS), safety, and monitorization of key circulating immune biomarkers (EU Clinical Trials Register number: EudraCT 2014-001620-29). RESULTS: After a median follow-up of 37 months, ORR was 60.2% [37.1% complete responses (CR) and 23.1% partial responses (PR)]. Median OS was 12 months (47 vs. 6 months in CR vs. no CR); median PFS was 9 months (34 vs. 5 months in CR vs. no CR). In the primary refractory population, ORR was 45.5% (21.2% CR and 24.3% PR). Most common grade 3-4 adverse events were thrombocytopenia (60.2%), neutropenia (60.2%), anemia (26.9%), infections (15.3%), and febrile neutropenia (14.1%). Complete responses were associated with a sharp decrease in circulating myeloid-derived suppressor cells and regulatory T cells. CONCLUSIONS: R2-GDP schedule is feasible and highly active in R/R DLBCL, including the primary refractory population. Immune biomarkers showed differences in responders versus progressors.

Peripheral T-cell lymphoma: molecular profiling recognizes subclasses and identifies prognostic markers.

Peripheral T-cell lymphoma (PTCL) is a clinically aggressive disease, with a poor response to therapy and a low overall survival rate of approximately 30% after 5 years. We have analyzed a series of 105 cases with a diagnosis of PTCL using a customized NanoString platform (NanoString Technologies, Seattle, WA) that includes 208 genes associated with T-cell differentiation, oncogenes and tumor suppressor genes, deregulated pathways, and stromal cell subpopulations. A comparative analysis of the various histological types of PTCL (angioimmunoblastic T-cell lymphoma [AITL]; PTCL with T follicular helper [TFH] phenotype; PTCL not otherwise specified [NOS]) showed that specific sets of genes were associated with each of the diagnoses. These included TFH markers, cytotoxic markers, and genes whose expression was a surrogate for specific cellular subpopulations, including follicular dendritic cells, mast cells, and genes belonging to precise survival (NF-κB) and other pathways. Furthermore, the mutational profile was analyzed using a custom panel that targeted 62 genes in 76 cases distributed in AITL, PTCL-TFH, and PTCL-NOS. The main differences among the 3 nodal PTCL classes involved the RHOAG17V mutations (P < .0001), which were approximately twice as frequent in AITL (34.09%) as in PTCL-TFH (16.66%) cases but were not detected in PTCL-NOS. A multivariate analysis identified gene sets that allowed the series of cases to be stratified into different risk groups. This study supports and validates the current division of PTCL into these 3 categories, identifies sets of markers that can be used for a more precise diagnosis, and recognizes the expression of B-cell genes as an IPI-independent prognostic factor for AITL.

Genomic mutation profile in progressive chronic lymphocytic leukemia patients prior to first-line chemoimmunotherapy with FCR and rituximab maintenance (REM).

Chronic Lymphocytic Leukemia (CLL) is the most prevalent leukemia in Western countries and is notable for its variable clinical course. This variability is partly reflected by the mutational status of IGHV genes. Many CLL samples have been studied in recent years by next-generation sequencing. These studies have identified recurrent somatic mutations in NOTCH1, SF3B1, ATM, TP53, BIRC3 and others genes that play roles in cell cycle, DNA repair, RNA metabolism and splicing. In this study, we have taken a deep-targeted massive sequencing approach to analyze the impact of mutations in the most frequently mutated genes in patients with CLL enrolled in the REM (rituximab en mantenimiento) clinical trial. The mutational status of our patients with CLL, except for the TP53 gene, does not seem to affect the good results obtained with maintenance therapy with rituximab after front-line FCR treatment.

An Overview on Diffuse Large B-Cell Lymphoma Models: Towards a Functional Genomics Approach.

Lymphoma research is a paradigm of the integration of basic and clinical research within the fields of diagnosis and therapy. Clinical, phenotypic, and genetic data are currently used to predict which patients could benefit from standard treatment. However, alternative therapies for patients at higher risk from refractoriness or relapse are usually empirically proposed, based on trial and error, without considering the genetic complexity of aggressive B-cell lymphomas. This is primarily due to the intricate mosaic of genetic and epigenetic alterations in lymphomas, which are an obstacle to the prediction of which drug will work for any given patient. Matching a patient's genes to drug sensitivity by directly testing live tissues comprises the "precision medicine" concept. However, in the case of lymphomas, this concept should be expanded beyond genomics, eventually providing better treatment options for patients in need of alternative therapeutic approaches. We provide an overview of the most recent findings in diffuse large B-cell lymphomas genomics, from the classic functional models used to study tumor biology and the response to experimental treatments using cell lines and mouse models, to the most recent approaches with spheroid/organoid models. We also discuss their potential relevance and applicability to daily clinical practice.

Circulating myeloid-derived suppressor cells and regulatory T cells as immunological biomarkers in refractory/relapsed diffuse large B-cell lymphoma: translational results from the R2-GDP-GOTEL trial.

BACKGROUND: The search for immunological markers with ability of predicting clinical outcome is a priority in lymphomas, and in cancer in general. It is well known that some immunomodulatory cells, such as myeloid derived suppressor cells (MDSCs) or regulatory T cells (Tregs), are recruited by tumors, jeopardizing antitumor immunosurveillance. In this work, we have studied blood levels of these immunosuppressive cells in patients with relapsed/refractory diffuse large B-cell lymphoma (R/R DLBCL), prior to and along the course of the experimental rituximab, gemcitabine, dexamethasone, and cisplatin (R2-GDP) schedule, as a translational substudy of the R2-GDP-GOTEL trial (EudraCT Number: 2014-001620-29), which included lenalidomide as an immunomodulator. METHODS: Blood samples were taken before treatment, at cycle 3 and end of induction. Samples were analyzed by flow cytometry. Non-parametric tests were used. Mann-Whitney U test was used to compare basal cells distributions, and Wilcoxon test was considered to compare cells distribution at different times. Spearman test was performed to measure the degree of association between cell populations. RESULTS: In this study, MDSC and Treg circulating concentration was found increased in all patients compared with a healthy control group and decreased after treatment only in patients with longest overall survival (>24 months), reaching the levels of the healthy group. Likewise, the number of inhibited T lymphocytes expressing Programmed Death-1 (PD-1) were increased in peripheral blood from patients and decreased on the treatment, whereas activated T lymphocytes increased after therapy in those with better overall survival. CONCLUSIONS: In conclusion, blood concentration of MDSCs and Treg cells may be good prognostic markers for overall survival after 2 years in R/R DLBCL. These results point to a possible role of these elements in the immunosuppression of these patients, as assessed by the circulating activated and inhibited T lymphocytes, and therefore, they may be considered as therapeutic targets in DLBCL.

Proposal and validation of a method to classify genetic subtypes of diffuse large B cell lymphoma.

Diffuse large B-cell lymphoma (DLBCL) is a heterogeneous disease whose prognosis is associated with clinical features, cell-of-origin and genetic aberrations. Recent integrative, multi-omic analyses had led to identifying overlapping genetic DLBCL subtypes. We used targeted massive sequencing to analyze 84 diagnostic samples from a multicenter cohort of patients with DLBCL treated with rituximab-containing therapies and a median follow-up of 6 years. The most frequently mutated genes were IGLL5 (43%), KMT2D (33.3%), CREBBP (28.6%), PIM1 (26.2%), and CARD11 (22.6%). Mutations in CD79B were associated with a higher risk of relapse after treatment, whereas patients with mutations in CD79B, ETS1, and CD58 had a significantly shorter survival. Based on the new genetic DLBCL classifications, we tested and validated a simplified method to classify samples in five genetic subtypes analyzing the mutational status of 26 genes and BCL2 and BCL6 translocations. We propose a two-step genetic DLBCL classifier (2-S), integrating the most significant features from previous algorithms, to classify the samples as N12-S, EZB2-S, MCD2-S, BN22-S, and ST22-S groups. We determined its sensitivity and specificity, compared with the other established algorithms, and evaluated its clinical impact. The results showed that ST22-S is the group with the best clinical outcome and N12-S, the more aggressive one. EZB2-S identified a subgroup with a worse prognosis among GCB-DLBLC cases.

Transformed follicular lymphoma in the rituximab era: A report from the Spanish Lymphoma Oncology Group.

Follicular lymphoma (FL) is the second most common non-Hodgkin lymphoma (NHL) subtype. The histological transformation (HT) of FL is an event considered frequent in the natural history of this tumor. We studied the transformation rates, predictive factors, and treatment characteristics that may impact in the survival of patients with FL and HT. A total of 1074 patients diagnosed with FL were prospectively enrolled from 1990 to 2016 in a Spanish registry. Sixty-four HTs were recorded based on clinical criteria (55%) or histological confirmation (45%). The cumulative incidence rate of transformation at 5 years is 7.3%. The 5-year overall survival (OS) without HT was 85% (95% confidence interval [CI], 70%-90%) vs 66% (95% CI, 51%-76%; P = 0.0012) with HT. Factors associated with HT were elevated lactate dehydrogenase (LDH) (odds ratio [OR] 1.83), intermediate-high Follicular lymphoma international prognostic index (FLIPI) (OR 2.16-OR 3.21), B symptoms (OR 2.46), or Eastern Cooperative Oncology Group (ECOG) 1 (OR 2.35). Treatment options related to HT were "watch and wait" or no rituximab or anthracyclines initially. A 5-year OS for patients treated with chemotherapy before HT was 55% (95% CI, 38%-69%) versus 81% (95% CI, 53%-93%; P = 0.009) for those who had not received it. The HT rate has decreased after the introduction of rituximab, as has been previously described. The timing of this treatment had an impact on the survival of these patients.

Unraveling transformation of follicular lymphoma to diffuse large B-cell lymphoma.

Follicular lymphoma (FL) is an indolent but largely incurable disease. Some patients suffer histological transformation to a more aggressive subtype with poorer prognosis. This study aimed to improve our understanding of the genetics underlying FL histological transformation, and to identify genetic drivers or promoters of the transformation by elucidating the differences between FL samples from patients who did and did not transform. We conducted targeted massive parallel sequencing of 22 pre-transformed FL/transformed diffuse large B-cell lymphoma pairs and 20 diagnostic samples from non-transformed FL patients. Additionally, 22 matched samples from 11 transformed FL patients (pre-transformed FL and diffuse large B-cell lymphoma) and 9 non-transformed FLs were studied for copy number variation using SNP arrays. We identified recurrently mutated genes that were enriched at transformation, most notably LRP1B, GNA13 and POU2AF1, which have roles in B-cell differentiation, GC architecture and migration. Mutations in POU2AF1 might be associated with lower levels of expression, were more frequent in transformed FLs, and seemed to be specific to transformed- compared with de novo-diffuse large B-cell lymphomas. Pre-transformed FLs carried more mutations per sample and had greater subclonal heterogeneity than non-transformed FLs. Finally, we identified four mutated genes in FL samples that differed between patients who did and did not transform: NOTCH2, DTX1, UBE2A and HIST1H1E. The presence of mutations in these genes was associated with shorter time to transformation when mutated in the FL biopsies. This information might be useful for identifying patients at higher risk of transformation.

Clonal dynamics monitoring during clinical evolution in chronic lymphocytic leukaemia.

Chronic lymphocytic leukaemia is the most prevalent leukaemia in Western countries. It is an incurable disease characterized by a highly variable clinical course. Chronic lymphocytic leukaemia is an ideal model for studying clonal heterogeneity and dynamics during cancer progression, response to therapy and/or relapse because the disease usually develops over several years. Here we report an analysis by deep sequencing of sequential samples taken at different times from the affected organs of two patients with 12- and 7-year disease courses, respectively. One of the patients followed a linear pattern of clonal evolution, acquiring and selecting new mutations in response to salvage therapy and/or allogeneic transplantation, while the other suffered loss of cellular tumoral clones during progression and histological transformation.

Overlap at the molecular and immunohistochemical levels between angioimmunoblastic T-cell lymphoma and a subgroup of peripheral T-cell lymphomas without specific morphological features.

The overlap of morphology and immunophenotype between angioimmunoblastic T-cell lymphoma (AITL) and other nodal peripheral T-cell lymphomas (n-PTCLs) is a matter of current interest whose clinical relevance and pathogenic background have not been fully established. We studied a series of 98 n-PTCL samples (comprising 57 AITL and 41 PTCL-NOS) with five TFH antibodies (CD10, BCL-6, PD-1, CXCL13, ICOS), looked for mutations in five of the genes most frequently mutated in AITL (TET2, DNMT3A, IDH2, RHOA and PLCG1) using the Next-Generation-Sequencing Ion Torrent platform, and measured the correlations of these characteristics with morphology and clinical features. The percentage of mutations in the RHOA and TET2 genes was similar (23.5% of cases). PLCG1 was mutated in 14.3%, IDH2 in 11.2% and DNMT3A in 7.1% of cases, respectively. In the complete series, mutations in RHOA gene were associated with the presence of mutations in IDH2, TET2 and DNMT3A (p < 0.001, p = 0.043, and p = 0.029, respectively). Fourteen cases featured RHOA mutations without TET2 mutations. A close relationship was found between the presence of these mutations and a TFH-phenotype in AITL and PTCL-NOS patients. Interestingly, BCL-6 expression was the only TFH marker differentially expressed between AITL and PTCL-NOS cases. There were many fewer mutated cases than there were cases with a TFH phenotype. Overall, these data suggest alternative ways by which neoplastic T-cells overexpress these proteins. On the other hand, no clinical or survival differences were found between any of the recognized subgroups of patients with respect to their immunohistochemistry or mutational profile.