Molecular insights into pathogenesis and targeted therapy of peripheral T cell lymphoma

Pre-treatment [18F]FDG PET/CT for assessing bone marrow involvement and prognosis in patients with newly diagnosed peripheral T-cell lymphoma

PURPOSE

To explore the value of [18F]fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) in assessing bone marrow involvement (BMI) and prognosis in newly diagnosed peripheral T-cell lymphomas (PTCLs) before treatment.

METHODS

This retrospective study included 201 eligible PTCLs who received pre-bone marrow biopsy (BMB) and PET/CT. The status of bone marrow (BM) by PET was assessed using a visual examination and a quantitative index (the maximal standardized uptake value [SUVmax] of BM divided by the SUVmax of the liver [M/L]).

RESULTS

Totally 148 patients had no evidence of BMI by PET or BMB; BMI was detected by both methods in 16 patients. The sensitivity and specificity of PET/CT for patients with confirmed BMI by BMB were 43.2% and 90.2%, respectively (κ =  0.353). In addition, 25 patients assessed by PET/CT staging (having stage I to II disease) had no evidence of BMI detected by both PET/CT and BMB. Image-guided biopsy was also recommended when PET/CT showed a focal FDG uptake outside the iliac crest. Survival analysis revealed that BMB was significant for overall survival (OS) (P = 0.020) while M/L for both progression free survival (P = 0.002) and OS (P < 0.001). In multivariate analysis, M/L (HR 1.825, 95% CI 1.071-3.110, P = 0.027) was an independent prognostic factor for OS. There were no statistical differences at the genetic level about BMI confirmed by PET or BMB.

CONCLUSION

PET/CT has a complementary role in assessing BMI and an ability to predict prognosis in PTCL patients.

Novel agents and regimens in relapsed or refractory peripheral T-cell lymphoma: latest updates from 2023 ASH annual meeting

Peripheral T-cell lymphoma (PTCL) is a heterogeneous group of hematological malignancies with poor survival, while treatment options for relapsed or refractory (R/R) disease remain quite limited, with a median progression-free survival of only 3-4 months. Notably, the emergence of innovative therapeutic agents and regimens holds promise for durable responses and improved survival for patients with R/R PTCL. We summarize recent advances in the treatment of R/R PTCL from the 2023 ASH Annual Meeting, highlighting novel agents targeting EZH1/2, JAK1, PI3K, KIR3DL2, CD38/CD3xCD28, or CDK9, as well as therapeutic regimens in combination with stem cell transplantation, immunomodulators, epigenetic modifying agents, or CD30/CD16A bispecific antibodies.

Role of plasma EBV-DNA load and EBER status on newly diagnosed peripheral T-cell lymphoma

PURPOSE

To explore the prognostic and therapeutic role of Epstein-Barr Virus (EBV) on peripheral T-cell lymphoma (PTCL).

METHODS

Totally 262 newly diagnosed PTCL patients who were hospitalized from January 2014 to December 2022 were retrospectively enrolled. Molecular analysis included 31 eligible patients. EBV-encoded RNA (EBER) presence in tumor tissue and EBV DNA levels in patients at baseline (DNA1) and after 4 cycles of chemotherapy (DNA4) were assessed.

RESULTS

Our findings revealed that the EBER-positive cohort exhibited significant differences compared to counterparts in overall survival (OS, P = 0.047) and progression-free survival (PFS, P = 0.009). Both DNA1 and DNA4 were significantly associated with inferior OS. Multivariate analysis demonstrated that DNA4 independently affected PTCL prognosis for OS (hazard ratio = 5.1617; 95% confidence interval 1.1017-24.1831; P = 0.037). Treatment with the cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) plus azacytidine regimen showed a better OS compared to CHOP or CHOP plus etoposide for patients with partially positive EBER and EBER positive statuses (P = 0.192), although the improvement was not statistically significant. This study delineated the genetic paradigm of PTCL, comparing genetic differences by EBV status and found that EBER partially positive plus positive patients were more likely to have DNMT3A (P = 0.002), RHOAG17V (P = 0.023), and TET2 mutations (P = 0.032).

CONCLUSION

EBER, DNA1, and DNA4 emerged as sensitive markers for prognosis. CHOP plus azacytidine might present a preferable option for PTCL patients with DNA methylation due to EBV infection.

Composite B-cell and T-cell lymphomas: clinical, pathological, and molecular features of three cases and literature review

Composite lymphoma (CL) involving B-cell lymphoma and T-cell lymphoma is extremely rare. Herein, we report three such cases using immunohistochemistry, flow cytometry, and the next-generation sequencing (NGS) to identify the pathological and molecular characteristics of CL. In the first case, the patient was admitted to hospital for generalized pruritic maculopapular rash over the whole body. An excisional biopsy of the skin lesions showed T-cell lymphoma. At the same time, the staging bone marrow (BM) biopsy revealed a diffuse large B-cell lymphoma (DLBCL). After R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone) therapies, the patient produced a good response with substantial dissipation of the rashes and relief of skin. The other two patients were admitted to hospital due to lymphadenopathy and were diagnosed with DLBCL and follicular lymphoma (FL) after core needle biopsy of lymph nodes, BM biopsy, BM aspiration, and flow cytometry. Following R-CHOP and R-COP (rituximab, cyclophosphamide, vincristine, and prednisone) therapies, they achieved complete remission unconfirmed (CRu) and complete remission (CR). However, one or two years later, they suffered a relapse of lymphadenopathy. The shocking fact was that re-biopsy of lymphadenopathy revealed peripheral T-cell lymphoma (PTCL) and angioimmunoblastic T-cell lymphoma (AITL). NGS findings identified DNA methyltransferase 3a (DNMT3a), isocitrate dehydrogenase 2 (IDH2), Ras homolog gene family, member A (RHOA), splicing factor 3B subunit 1 (SF3B1), and tumor protein p53 (TP53) mutations. After immunochemotherapy, these patients achieved CRu and CR again. Nevertheless, they suffered a second relapse of T-cell lymphoma. Finally, they died due to progression of disease. We found that the occurrence of CL is associated with Epstein-Barr virus infection and DNMT3a, IDH2, and TP53 mutations, and the prognosis of the disease is closely related to the T-cell lymphoma components.

Misdiagnosis of angioimmunoblastic T‑cell lymphoma: A case report

Angioimmunoblastic T-cell lymphoma (AITL) is a specific subtype of peripheral T-cell lymphoma that is challenging to diagnose due to the lack of specific pathological characteristics. This report describes the case of a 56-year-old man with Hodgkin lymphoma in whom the gene rearrangement results were positive for TCRβDB+Jβ1/2. Pathological and immunochemical examinations revealed a diagnosis of lymphoma that was a composite of AITL and focal classical Hodgkin lymphoma. Unfortunately, he died soon after the correct diagnosis was made. This case shows that a combination of immunohistochemistry and gene rearrangement analysis can increase the diagnostic accuracy for AITL. A review of the literature on the misdiagnosis of AITL indicates that this disease progresses rapidly with a high mortality rate. Our experience, in this case, highlights the need for early diagnosis.

A nodal EBV-positive T cell lymphoma with a T follicular helper cell phenotype

AIMS

Nodal T follicular helper (TFH) cell lymphoma (nTFHL) is a rare type of clinically aggressive T cell lymphoma. With this lymphoma type, Epstein-Barr virus (EBV) infection is frequently detected in non-neoplastic B lymphocytes, but not yet identified in neoplastic T cells. We report two cases of nTFHL showing a classic morphology and immunoprofile, with EBV-encoded small RNAs (EBER) in-situ hybridisation positivity in neoplastic TFH cells.

METHODS AND RESULTS

Clonal T cell receptor (TR) gene rearrangement was detected in both cases. Whole exome sequencing identified TET2, RHOA p. G17V, as well as gene mutations unique to each case. Microdissection analysis showed EBER positivity in tumour cells and in background non-neoplastic T lymphocytes.

CONCLUSION

These two immunocompetent cases of nTFHL with EBV-positive tumour cells exhibit the featured gene mutation profile and poor prognosis of this disease. This novel finding of EBV positivity in our cases expands the currently recognised spectrum of EBV-positive nodal T cell lymphomas to include rare cases of nTFHL.

Circulating Tumor DNA-Based Genotyping and Monitoring for Predicting Disease Relapses of Patients with Peripheral T-Cell Lymphomas

PURPOSE

Plasma circulating tumor DNA (ctDNA) could reflect the genetic alterations present in tumor tissues. However, there is little information about the clinical relevance of cell-free DNA genotyping in peripheral T-cell lymphoma (PTCL).

MATERIALS AND METHODS

After targeted sequencing plasma cell-free DNA of patients with various subtypes of PTCL (n=94), we analyzed the mutation profiles of plasma ctDNA samples and their predictive value of dynamic ctDNA monitoring for treatment outcomes.

RESULTS

Plasma ctDNA mutations were detected in 53 patients (56%, 53/94), and the detection rate of somatic mutations was highest in angioimmunoblastic T-cell lymphoma (24/31, 77%) and PTCL, not otherwise specified (18/29, 62.1%). Somatic mutations were detected in 51 of 66 genes that were sequenced, including the following top 10 ranked genes: RHOA, CREBBP, KMT2D, TP53, IDH2, ALK, MEF2B, SOCS1, CARD11, and KRAS. In the longitudinal assessment of ctDNA mutation, the difference in ctDNA mutation volume after treatment showed a significant correlation with disease relapse or progression. Thus, a ≥ 1.5-log decrease in genome equivalent (GE) between baseline and the end of treatment showed a significant association with better survival outcomes than a < 1.5-log decrease in GE.

CONCLUSION

Our results suggest the clinical relevance of plasma ctDNA analysis in patients with PTCL. However, our findings should be validated by a subsequent study with a larger study population and using a broader gene panel.

Mucosal-Associated Invariant T Cells in T-Cell Non-Hodgkin Lymphomas: A Case Series

Simple Summary

Mucosal-associated invariant T (MAIT) cells are a subgroup of T lymphocytes whose role has recently been investigated in several types of diseases, including cancer. However, little is known about these cells in lymphomas. In this case series, we investigated the presence of MAIT cells in biopsies obtained from patients diagnosed with T-cell non-Hodgkin lymphomas, uncommon hematological malignancies with often not clearly defined etiopathology.

Abstract

Background: Mucosal-associated invariant T (MAIT) cells are a subset of unconventional T lymphocytes expressing a semi-invariant α/β T-cell receptor (TCR). The physiological functions of these cells, which are particularly abundant in normal liver and mucosal sites, have become clear only in recent years, but their role in most human diseases is still unknown. Since the cellular origin and etiopathogenesis of most T-lymphomas are still elusive, we decided to explore the presence of MAIT cells in biopsies from these neoplasms. Methods: Sixteen biopsies obtained from patients with a T-cell lymphoma diagnosis were analyzed via immunofluorescence staining using an anti-Vα7.2 antibody and the MR1-antigen tetramer. Positive cases were subjected to a polymerase chain reaction for the detection of Vα7.2–Jα33, Vα7.2–Jα20, or Vα7.2–Jα12 rearrangements, followed by sequencing of the CDR3α region. Results: CD3+/Vα7.2+ and CD3+/MR1-Ag-tetramer+ cells were found in 4 of 16 samples analyzed. The identification of specific TCR rearrangements confirmed the presence of these cells in all four samples. PCR and sequencing results documented the presence of multiple clones of MAIT cells in each positive sample. Conclusions: MAIT cells are frequently found in T-cell lymphomas. More in-depth studies and a larger number of samples are needed to better clarify the contribution of MAIT cells to this rare neoplasm.

Epi-immunotherapy for cancers: rationales of epi-drugs in combination with immunotherapy and advances in clinical trials

Over the last two decades, several epi-drugs, immune checkpoint inhibitors (ICIs) and adoptive cell therapies have received clinical approval for use in certain types of cancer. However, monotherapy with epi-drugs or ICIs has shown limited efficacy in most cancer patients. Epigenetic agents have been shown to regulate the crosstalk between the tumor and host immunity to alleviate immune evasion, suggesting that epi-drugs can potentially synergize with immunotherapy. In this review, we discuss recent insights into the rationales of incorporating epigenetic therapy into immunotherapy, called epi-immunotherapy, and focus on an update of current clinical trials in both hematological and solid malignancies. Furthermore, we outline the future challenges and strategies in the field of cancer epi-immunotherapy.

Genetic Landscape of Peripheral T-Cell Lymphoma

Peripheral T-Cell lymphoma (PTCL) comprises a heterogenous group of uncommon lymphomas derived from mature, post-thymic or “peripheral” T- and natural killer cells. The World Health Organization (WHO) emphasizes a multiparameter approach in the diagnosis and subclassification of these neoplasms, integrating clinical, morphologic, immunophenotypic, and genetic features into the final diagnosis. Clinical presentation is particularly important due to histologic, immunophenotypic and genetic variations within established subtypes, and no convenient immunophenotypic marker of monoclonality exists. In recent years, widespread use of gene expression profiling and next-generation sequencing (NGS) techniques have contributed to an improved understanding of the pathobiology in PTCLs, and these have been incorporated into the 2016 revised WHO classification of mature T- and NK-cell neoplasms which now encompasses nearly 30 distinct entities. This review discusses the genetic landscape of PTCL and its role in subclassification, prognosis, and potential targeted therapy. In addition to discussing T-Cell lymphoma subtypes with relatively well-defined or relevant genetic aberrancies, special attention is given to genetic advances in T-Cell lymphomas of T follicular helper cell (TFH) origin, highlighting genetic overlaps between angioimmunoblastic T-Cell lymphoma (AITL), follicular T-Cell lymphoma, and nodal peripheral T-Cell lymphoma with a TFH phenotype. Furthermore, genetic drivers will be discussed for ALK-negative anaplastic large cell lymphomas and their role in differentiating these from CD30+ peripheral T-Cell lymphoma, not otherwise specified (NOS) and primary cutaneous anaplastic large cell lymphoma. Lastly, a closer look is given to genetic pathways in peripheral T-Cell lymphoma, NOS, which may guide in teasing out more specific entities in a group of T-Cell lymphomas that represents the most common subcategory and is sometimes referred to as a “wastebasket” category.

Differential diagnosis and identification of prognostic markers for peripheral T-cell lymphoma subtypes based on flow cytometry immunophenotype profiles

We compared the differential expression of 15 markers in PTCL (Peripheral T-cell lymphoma) subtypes and T-CUS (T-cell clones of uncertain significance), and summarized the specific immunophenotype profiles of each subtype and its impact on prognosis. PD-1 and CD10 are diagnostic markers for AITL (angioimmunoblastic T-cell lymphoma). To avoid confusion with T-CUS of benign clones, it is recommended to define AITL as bounded by PD-1+%>38.01 and/or CD10+%>7.46. T cell-derived ENKTL-N (extranodal NKT cell lymphoma) specifically expresses CD56. ALCL (anaplastic large cell lymphoma) characteristically expresses CD30 and HLA-DR. PTCL-NOS (peripheral T-cell lymphoma unspecified) still lacks a relatively specific phenotype and is prone to loss of basic lineage markers CD3, CD5, and CD7. The determination of T-CUS can be verified by the overall assessment of the bone marrow and a certain period of follow-up. The clustering results showed that the expression of 8 specific markers was significantly different among the 5 groups, suggesting that a combination of related markers can be analyzed in the identification of PTCLs subtypes. The study explores the advantages of TRBC1 combined with CD45RA/CD45RO in detecting T cell clonality, which can efficiently and sensitively analyze multiple target T cell populations at the same time. The sensitivity of PB to replace BM to monitor the tumor burden or MRD (minimal residual disease) of PTCLs is as high as 85.71%, which can relieve the huge pressure of clinical sampling and improve patient compliance. CD7, CD38, and Ki-67 are prognostic indicators for AITL. CD3 and CD8 on PTCL-NOS, and CD56 and HLA-DR on ENKTL-N have prognostic role. This study supports and validates the current classification of PTCL subtypes and establishes an immunophenotypic profile that can be used for precise diagnosis. The important clinical value of PTCLs immunophenotype in routine classification diagnosis, clonality confirmation, prognosis prediction, and treatment target selection was emphasized.

Cytomorphological characterisation of angioimmunoblastic T cell lymphoma: a case-control study

AIMS

Angioimmunoblastic T cell lymphoma (AITL) is often misdiagnosed in cytology. Hence, the present study was conducted to identify the distinctive cytomorphological features of AITL in lymph node fine-needle aspirates (LN-FNA).

METHODS

This was a 4-year retrospective case-control study. Cases included LN-FNAs from patients with histopathologically confirmed AITL. The controls included LN-FNAs from patients with histopathologically confirmed reactive lymphoid hyperplasia (RLH; n=25). Eleven cytomorphological features were assessed in all the aspirates; the strength of association was determined by OR, Cramer's V and multiple correspondence analysis (MCA).

RESULTS

Of a total of 22 cases of AITL reported on histopathology, 19 adequate aspirates from 14 patients (63.6%) were available for review. On univariate analysis, 5 of 11 cytomorphological variables were found to be significant for AITL; however, on MCA, 3 of these parameters, viz absence of tingible body macrophages (OR=0.014; V=0.74), presence of atypical lymphoid cells (OR=10.8; V=0.41) and singly scattered epithelioid cells (OR=19.3; V=0.31), were found to be the strongest predictors of AITL.

CONCLUSIONS

The absence of tingible body macrophages, presence of atypical lymphoid cells and singly scattered epithelioid cells in polymorphic LN-FNAs are significant cytomorphological predictors of AITL in comparison with RLH. Knowledge of these diagnostic predictors, supplemented by clinicoradiological correlation and appropriate ancillary studies, can help diagnose AITL on aspiration cytology.

Characteristics of genetic alterations of peripheral T-cell lymphoma in childhood including identification of novel fusion genes: the Japan Children's Cancer Group (JCCG)

Peripheral T-cell lymphoma (PTCL) is a group of heterogeneous non-Hodgkin lymphomas showing a mature T-cell or natural killer cell phenotype, but its molecular abnormalities in paediatric patients remain unclear. By employing next-generation sequencing and multiplex ligation-dependent probe amplification of tumour samples from 26 patients, we identified somatic alterations in paediatric PTCL including Epstein-Barr virus (EBV)-negative (EBV^- ) and EBV-positive (EBV⁺ ) patients. As recurrent mutational targets for PTCL, we identified several previously unreported genes, including TNS1, ZFHX3, LRP2, NCOA2 and HOXA1, as well as genes previously reported in adult patients, e.g. TET2, CDKN2A, STAT3 and TP53. However, for other reported mutations, VAV1-related abnormalities were absent and mutations of NRAS, GATA3 and JAK3 showed a low frequency in our cohort. Concerning the association of EBV infection, two novel fusion genes: STAG2-AFF2 and ITPR2-FSTL4, and deletion and alteration of CDKN2A/2B, LMO1 and HOXA1 were identified in EBV^- PTCL, but not in EBV⁺ PTCL. Conversely, alterations of PCDHGA4, ADAR, CUL9 and TP53 were identified only in EBV⁺ PTCL. Our observations suggest a clear difference in the molecular mechanism of onset between paediatric and adult PTCL and a difference in the characteristics of genetic alterations between EBV^- and EBV⁺ paediatric PTCL.

Comprehensive analysis of clinical, pathological, and genomic characteristics of follicular helper T-cell derived lymphomas

Background

The 2016 World Health Organization (WHO) classification introduced nodal lymphomas of T follicular helper (Tfh) cell origin, such as angioimmunoblastic T-cell lymphoma (AITL), follicular peripheral T-cell lymphoma (F-PTCL), and nodal peripheral T-cell lymphoma with T follicular helper phenotype (nodal PTCL with TFH phenotype). However, the accurate incidence rate and clinical characteristics of F-PTCL and nodal PTCL with TFH are unstudied.

Methods

Between February 2012 to June 2020, a total of 207 cases diagnosed with nodal lymphomas of T follicular helper (Tfh) cell origin and PTCL-NOS were reviewed for clinical and histopathologic data. PTCL-NOS was defined to not correlate to any of the specific entities of mature T cell lymphoma in the WHO 2016 classification. We attempted to classify PTCL-GATA3 and PTCL-TBX21 by IHC staining. Target gene analysis was performed on a few patients with sufficient blood and tissue samples additionally.

Results

Among 207 patients, 111 patients (53.6%) had AITL, 67 patients (32.4%) had PTCL-NOS, 19 patients (9.2%) had F-PTCL, and 10 patients (4.8%) had nodal PTCL with TFH phenotype. We re-defined and analyzed F-PTCL and nodal PTCL with TFH phenotype into other TFH lymphomas. AITL (N = 101/111, 91.0%) was found to have a higher frequency of stage III/IV cancers compared to other TFH lymphomas (N = 22/29, 75.0%) and PTCL-NOS (N = 53/67, 79.1%; p-value = 0.03). The OS of AITL and other TFH lymphomas was similarly superior to PTCL-NOS (p-value = 0.02). AITL and other TFH lymphomas showed the TBX21 subtype more commonly than the GATA3 subtype. Mutations related to the RAS family (RHOA) and those related to epigenetic regulators (IDH2, DNMT3A, and TET2) were shown mainly in AITL and other TFH lymphomas.

Conclusions

Other TFH lymphomas appear to be a rare disease entity around one-quarter in nodal lymphomas of T follicular helper (Tfh) cell origin. Their less aggressive clinical feature than we did not expect is utterly different from PTCL-NOS and AITL. On the other hand, other TFH lymphomas share some characteristics, such as the cell of origin, a more common TBX21 subtype, and genetic variation such as RAS family mutation and epigenetic regulators, with AITL.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40164-021-00224-3.