Double-hit Signature with TP53 Abnormalities Predicts Poor Survival in Patients with Germinal Center Type Diffuse Large B-cell Lymphoma Treated with R-CHOP

Transformation of marginal zone lymphoma into high-grade B-cell lymphoma expressing terminal deoxynucleotidyl transferase: A case report

BACKGROUND

High-grade B-cell lymphoma (HGBL) is an unusual malignancy that includes myelocytomatosis viral oncogene (MYC), B-cell lymphoma-2 (BCL-2), and/or BCL-6 rearrangements, termed double-hit or triple-hit lymphomas, and HGBL-not otherwise specific (HGBL-NOS), which are morphologically characteristic of HGBL but lack MYC, BCL-2, or BCL-6 rearrangements. HGBL is partially transformed by follicular lymphoma and other indolent lymphoma, with few cases of marginal zone lymphoma (MZL) transformation. HGBL often has a poor prognosis and intensive therapy is currently mainly advocated, but there is no good treatment for these patients who cannot tolerate chemotherapy.

CASE SUMMARY

We reported a case of MZL transformed into HGBL-NOS with TP53 mutation and terminal deoxynucleotidyl transferase expression. Gene analysis revealed the gene expression profile was identical in the pre- and post-transformed tissues, suggesting that the two diseases are homologous, not secondary tumors. The chemotherapy was ineffective and the side effect was severe, so we tried combination therapy including venetoclax and obinutuzumab. The patient tolerated treatment well, and reached partial response. The patient had recurrence of hepatocellular carcinoma and died of multifunctional organ failure. He survived for 12 months after diagnosis.

CONCLUSION

Venetoclax combined with obinutuzumab might improve the survival in some HGBL patients, who are unsuitable for chemotherapy.

Distribution and clinical impact of molecular subtypes with dark zone signature of DLBCL in a Japanese real-world study

The distribution and clinical impact of cell-of-origin (COO) subtypes of diffuse large B-cell lymphoma (DLBCL) outside Western countries remain unknown. Recent literature also suggests that there is an additional COO subtype associated with the germinal center dark zone (DZ) that warrants wider validation to generalize clinical relevance. Here, we assembled a cohort of Japanese patients with untreated DLBCL and determined the refined COO subtypes, which include the DZ signature (DZsig), using the NanoString DLBCL90 assay. To compare the distribution and clinical characteristics of the molecular subtypes, we used a data set from the cohort of British Columbia Cancer (BCC) (n = 804). Through the 1050 patient samples on which DLBCL90 assay was successfully performed in our cohort, 35%, 45%, and 6% of patients were identified to have germinal center B-cell-like (GCB) DLBCL, activated B-cell-like (ABC) DLBCL, and DZsig-positive (DZsigpos) DLBCL, respectively, with the highest prevalence of ABC-DLBCL, differing significantly from the BCC result (P < .001). GCB-DLBCL, ABC-DLBCL, and DZsigpos-DLBCL were associated with 2-year overall survival rates of 88%, 75%, and 66%, respectively (P < .0001), with patients with DZsigpos-DLBCL having the poorest prognosis. In contrast, GCB-DLBCL without DZsig showed excellent outcomes after rituximab-containing immunochemotherapy. DZsigpos-DLBCL was associated with the significant enrichment of tumors with CD10 expression, concurrent MYC/BCL2 expression, and depletion of microenvironmental components (all, P < .05). These results provide evidence of the distinct distribution of clinically relevant molecular subtypes in Japanese DLBCL and that refined COO, as measured by the DLBCL90 assay, is a robust prognostic biomarker that is consistent across geographical areas.

High-grade B-cell lymphoma, not otherwise specified: a multi-institutional retrospective study

In this multi-institutional retrospective study, we examined the characteristics and outcomes of 160 patients with high-grade B-cell lymphoma, not otherwise specified (HGBL-NOS)-a rare category defined by high-grade morphologic features and lack of MYC rearrangements with BCL2 and/or BCL6 rearrangements ("double hit"). Our results show that HGBL-NOS tumors are heterogeneous: 83% of patients had a germinal center B-cell immunophenotype, 37% a dual-expressor immunophenotype (MYC and BCL2 expression), 28% MYC rearrangement, 13% BCL2 rearrangement, and 11% BCL6 rearrangement. Most patients presented with stage IV disease, a high serum lactate dehydrogenase, and other high-risk clinical factors. Most frequent first-line regimens included dose-adjusted cyclophosphamide, doxorubicin, vincristine, and etoposide, with rituximab and prednisone (DA-EPOCH-R; 43%); rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP; 33%); or other intensive chemotherapy programs. We found no significant differences in the rates of complete response (CR), progression-free survival (PFS), or overall survival (OS) between these chemotherapy regimens. CR was attained by 69% of patients. PFS at 2 years was 55.2% and OS was 68.1%. In a multivariable model, the main prognostic factors for PFS and OS were poor performance status, lactate dehydrogenase >3 × upper limit of normal, and a dual-expressor immunophenotype. Age >60 years or presence of MYC rearrangement were not prognostic, but patients with TP53 alterations had a dismal PFS. Presence of MYC rearrangement was not predictive of better PFS in patients treated with DA-EPOCH-R vs R-CHOP. Improvements in the diagnostic criteria and therapeutic approaches beyond dose-intense chemotherapy are needed to overcome the unfavorable prognosis of patients with HGBL-NOS.

Hepatitis B Virus and B-cell lymphoma: evidence, unmet need, clinical impact, and opportunities

Nearly a billion people worldwide are infected with the hepatitis B Virus (HBV) and about a third of them have chronic infection. HBV is an important cause of morbidity and mortality, including acute and chronic hepatitis and hepatocellular carcinoma (HCC). Screening and control of primary HBV infection through vaccination represent a major advance in global public health, but large sections of the world population, in both developed and underdeveloped countries, remain unscreened and unvaccinated. In addition to being a global cause of liver disease, an important role of HBV in lymphoma has also emerged. First, the high risk of HBV reactivation in previously infected patients receiving chemo-immunotherapy necessitates the systematic evaluation of HBV serological status in all non-Hodgkin's lymphoma (NHL) cases and preemptive antiviral therapy for those who may have chronic or occult HBV infection. Second, HBV has been shown to infect lymphocytes, namely B-cells, and has been associated with a higher risk of developing B-cell lymphoma, most clearly in countries where HBV is endemic. While the risk of HBV reactivation with chemoimmunotherapy in NHL is well known, the role and the impact of HBV as a global lymphoma risk factor and potential oncogenic driver in B-cells are very poorly understood. Here, we review the clinical and scientific evidence supporting an association between HBV and B-cell lymphoma, with a particular focus on diffuse large B-cell lymphoma (DLBCL) and provide an overview of the estimated impact of HBV infection on the biology and clinical course of DLBCL. We also discuss ways to gain a better insight into the unmet need posed by HBV in lymphoma and whether assessing immune responses to HBV, measuring viral loads, and detecting the presence of HBV-encoded proteins in tumor tissue could be integrated into the molecular and clinical risk stratification of patients with DLBCL.

p53 as Exemplar Next-Generation Immunohistochemical Marker: A Molecularly Informed, Pattern-Based Approach, Methodological Considerations, and Pan-Cancer Diagnostic Applications

This review is based on a webinar I presented for the International Society for Immunohistochemistry and Molecular Morphology (ISIMM) in February 2022. It is intended that all ISIMM webinars will ultimately be published in AIMM as review articles. This work is also dedicated to Clive Taylor, who has deeply impacted my career. It presents a molecularly informed, pattern-based approach to p53 immunohistochemistry interpretation, methodological considerations (ie, antibody selection, optimization, validation, controls, and external quality assessment), and pan-cancer diagnostic applications, including those drawn from gastrointestinal, genitourinary, gynecological, neuroendocrine, hematologic, and neuropathology. It intends to prove the thesis statement that p53 is an exemplar next-generation immunohistochemical marker "born" ahead of its time.

Sequence analyses of relapsed or refractory diffuse large B-cell lymphomas unravel three genetic subgroups of patients and the GNA13 mutant as poor prognostic biomarker, results of LNH-EP1 study

Advances in molecular profiling of newly diagnosed diffuse large B-cell lymphoma (DLBCL) have recently refine genetic subgroups. Genetic subgroups remain undetermined at the time of relapse or refractory (RR) disease. This study aims to decipher genetic subgroups and search for prognostic molecular biomarkers in patients with RR-DLBCL. From 2015 to 2021, targeted next-generation sequencing analyses of germline-matched tumor samples and fresh tissue from RR-DLBCL patients were performed. Unsupervised clustering of somatic mutations was performed and correlations with patient outcome were sought. A number of 120 patients with RR-DLBCL were included in LNH-EP1 study and a molecular tumor landscape was successfully analyzed in 87% of patients (104/120 tumor samples). The median age was 67.5 years (range 27.4-87.4), median number of previous treatments was 2 (range 1-9). The most frequently mutated genes were TP53 (n = 53 mutations; 42% of samples), CREBBP (n = 39; 32%), BCL2 (n = 86; 31%), KMT2D (n = 39; 28%) and PIM1 (n = 54; 22%). Unsupervised clustering separated three genetic subgroups entitled BST (enriched in BCL2, SOCS1, and TNFRSF14 mutations); TKS (enriched in TP53, KMT2D, and STAT6 mutations); and PCM (enriched in PIM1, CD79B, and MYD88 mutations). Median overall survival (OS) was 11.0 (95% confidence interval [CI]: 8.1-12.6) months. OS was not significantly different between the three genetic subgroups. GNA13 mutant was significantly associated with an increased risk of death (hazard ratio: 6.6 [95% CI: 2.1-20.6]; p = .0011) and shorter OS (p = .0340). At the time of relapse or refractory disease, three genetic subgroups of DLBCL patients were delineated, which could help advance precision molecular medicine programs.

High-grade B-cell lymphoma with concurrent MYC rearrangement and 11q aberrations: Clinicopathologic, cytogenetic and molecular characterization of 4 cases

High-grade B-cell lymphoma with 11q aberrations (LBL-11q) resembles Burkitt lymphoma (BL), is negative for MYC rearrangement, and harbors chromosome 11q aberrations. Rare cases of high-grade B-cell lymphoma with concurrent MYC rearrangement and 11q aberrations (HGBCL-MYC-11q) have been described. In this study we report the clinicopathologic, cytogenetic, and molecular findings in 4 such cases. Diagnoses were made on tissue or bone marrow biopsies. Karyotype, fluorescence in situ hybridization, genomic microarray analyses, and next-generation sequencing were performed. All patients were male (median age 39 years). Three cases were diagnosed as BL, while one was diagnosed as diffuse large B-cell lymphoma. Karyotypes (available in 2 patients) were complex. In one patient, copy number analysis showed gains at 1q21.1-q44 and 13q31.3, and loss of 13q34, abnormalities typically seen in BL. All of our cases showed two or more mutations that are recurrent in BL, including ID3, TP53, DDX3X, CCND3, FBXO1, and MYC. Two cases showed a GNA13 mutation, commonly seen in LBL-11q. Cases of HGBCL-MYC-11q display overlapping morphologic and immunophenotypic, as well as cytogenetic and molecular features between BL and LBL-11q, with a mutational landscape enriched for mutations recurrent in BL. Concurrent MYC rearrangement with 11q abnormalities is important to recognize especially since it has implications for their classification.

EZH1/2 as targets for cancer therapy

The enhancer of zeste homolog 2 (EZH2) and its highly related homolog EZH1 are considered to be epigenetic silencing factors, and they play key roles in the growth and differentiation of cells as the core components of polycomb repressive complex 2 (PRC2). EZH1 and EZH2 are known to have a role in human malignancies, and alterations in these two genes have been implicated in transformation of human malignancies. Inhibition of EZH1/2 has been shown to result in tumor regression in humans and has been studied and evaluated in the preclinical setting and in multiple clinical trials at various levels. Our work thus contributes to the understanding of the relationship between regulatory molecules associated with EZH1/2 proteins and tumor progression, and may provide new insights for mechanism-based EZH1/2-targeted therapy in tumors.

Diagnostic approaches and future directions in Burkitt lymphoma and high-grade B-cell lymphoma

Since the 2016 WHO update, progress has been made in understanding the biology of Burkitt lymphoma (BL) and the concept of high-grade B-cell lymphomas (HGBCL) that allows some degree of refinement. The summary presented here reviews in detail the discussions of the Clinical Advisory Committee and expands upon the newly published 2022 International Consensus Classification for lymphoid malignancies (Campo et al. Blood, 2022). BL remains the prototypic HGBCL and diagnostic criteria are largely unchanged. HGBCL with MYC and BCL2 and HGBCL with MYC and BCL6 rearrangements are now separated to reflect biologic and pathologic differences. HGBCL, NOS remains a diagnosis of exclusion that should be used only in rare cases. FISH strategies for diffuse large B-cell lymphoma (DLBCL) and HGBCL are discussed in detail for these diseases. Advances in integrative analysis of mutations, structural abnormalities, copy number, and gene expression signatures allow a more nuanced view of the heterogeneity of DLBCL, NOS as well as definitions of HGBCL and point to where the future may be headed for classification of these diseases.

Efficacy and safety of CD19-specific CAR-T cell-based therapy in secondary central nervous system lymphoma

Encouraging response has been achieved in relapsed/refractory (R/R) B-cell lymphoma treated by chimeric antigen receptor T (CAR-T) cells. The efficacy and safety of CAR-T cells in central nervous system lymphoma (CNSL) are still elusive. Here, we retrospectively analyzed 15 patients with R/R secondary CNSL receiving CD19-specific CAR-T cell-based therapy. The patients were infused with CD19, CD19/CD20 or CD19/CD22 CAR-T cells following a conditioning regimen of cyclophosphamide and fludarabine. The overall response rate was 73.3% (11/15), including 9 (60%) with complete remission (CR) and 2 (13.3%) with partial remission (PR). During a median follow-up of 12 months, the median progression-free survival (PFS) was 4 months, and the median overall survival (OS) was 9 months. Of 12 patients with systemic tumor infiltration, 7 (58.3%) achieved CR in CNS, and 5 (41.7%) achieved CR both systemically and in CNS. Median DOR for CNS and systemic disease were 8 and 4 months, respectively. At the end point of observation, of the 7 patients achieved CNS disease CR, one was still alive with sustained CR of CNS disease and systemic disease. The other 6 died of systemic progression. Of the 15 patients, 11 (73.3%) experienced grades 1-2 CRS, and no patient had grades 3-4 CRS. Immune effector cell-associated neurotoxicity syndrome (ICANS) occurred in 3 (20%) patients, including 1 (6.6%) with grade 4 ICANS. All the CRS or ICANS were manageable. The CD19-specific CAR-T cell-based therapy appeared to be a promising therapeutic approach in secondary CNSL, based on its antitumor effects and an acceptable side effect profile, meanwhile more strategies are needed to maintain the response.

Fitting double-hit lymphoma into the aggressive lymphoma spectrum: a square peg in a round hole?

High-grade B-cell lymphoma with MYC and BCL2 and/or BCL6 rearrangements or both, commonly called double-hit lymphoma (DHL), is an aggressive B-cell lymphoma that is molecularly distinct from diffuse large B-cell lymphoma (DLBCL) and is associated with poor outcomes. Recent advances in the molecular classification of DLBCL have identified distinct subsets, including genetic signatures which correlate with DHL and survival. DHL with concomitant TP53 mutation appears to be associated with a very poor prognosis. Standard chemo-immunotherapy is not an effective treatment for these patients and personalized, innovative strategies are needed. In this review, we summarize recent advances in the subclassification of DLBCL, with a focus on DHL. We also incorporate early, promising clinical trial data using CAR T and targeted therapies. Rationally designed clinical trials for DLBCL are needed to advance the care of patients with DHL and other adverse risk DLBCL subgroups.

Altered pathways and targeted therapy in double hit lymphoma

High-grade B-cell lymphoma with translocations involving MYC and BCL2 or BCL6, usually referred to as double hit lymphoma (DHL), is an aggressive hematological malignance with distinct genetic features and poor clinical prognosis. Current standard chemoimmunotherapy fails to confer satisfying outcomes and few targeted therapeutics are available for the treatment against DHL. Recently, the delineating of the genetic landscape in tumors has provided insight into both biology and targeted therapies. Therefore, it is essential to understand the altered signaling pathways of DHL to develop treatment strategies with better clinical benefits. Herein, we summarized the genetic alterations in the two DHL subtypes (DHL-BCL2 and DHL-BCL6). We further elucidate their implications on cellular processes, including anti-apoptosis, epigenetic regulations, B-cell receptor signaling, and immune escape. Ongoing and potential therapeutic strategies and targeted drugs steered by these alterations were reviewed accordingly. Based on these findings, we also discuss the therapeutic vulnerabilities that coincide with these genetic changes. We believe that the understanding of the DHL studies will provide insight into this disease and capacitate the finding of more effective treatment strategies.

Molecular features encoded in the ctDNA reveal heterogeneity and predict outcome in high-risk aggressive B-cell lymphoma

Inadequate molecular and clinical stratification of the patients with high-risk diffuse large B-cell lymphoma (DLBCL) is a clinical challenge hampering the establishment of personalized therapeutic options. We studied the translational significance of liquid biopsy in a uniformly treated trial cohort. Pretreatment circulating tumor DNA (ctDNA) revealed hidden clinical and biological heterogeneity, and high ctDNA burden determined increased risk of relapse and death independently of conventional risk factors. Genomic dissection of pretreatment ctDNA revealed translationally relevant phenotypic, molecular, and prognostic information that extended beyond diagnostic tissue biopsies. During therapy, chemorefractory lymphomas exhibited diverging ctDNA kinetics, whereas end-of-therapy negativity for minimal residual disease characterized cured patients and resolved clinical enigmas, including false residual PET positivity. Furthermore, we discovered fragmentation disparities in the cell-free DNA that characterize lymphoma-derived ctDNA and, as a proof-of-concept for their clinical application, utilized machine learning to show that end-of-therapy fragmentation patterns predict outcome. Altogether, we have discovered novel molecular determinants in the liquid biopsy that can non-invasively guide treatment decisions.

Double-hit lymphoma: optimizing therapy

Aggressive B-cell lymphoma is a heterogeneous entity with disparate outcomes based on clinical and pathological characteristics. While most tumors in this category are diffuse large B-cell lymphoma (DLBCL), the recognition that some cases have high-grade morphology and frequently harbor MYC and BCL2 and/or BCL6 translocations has led to their separate categorization. These cases are now considered distinct from DLBCL and are named "high-grade B-cell lymphoma" (HGBL). Most are characterized by distinct rearrangements, but others have high-grade morphological features without these and are called HGBL-not otherwise specified. Studies have demonstrated that this group of diseases leads to poor outcomes following standard rituximab, cyclophosphamide, hydroxydaunorubicin, vincristine, and prednisone therapy; retrospective and recent single-arm, multicenter studies suggest they should be approached with dose-intense treatment platforms. As yet, this has not been validated in randomized trial settings due to the rarity of these diseases. In the relapsed and refractory setting, novel approaches such as anti-CD19 chimeric antigen receptor T cells and antibodies against CD19 have demonstrated high efficacy in this subgroup. Recently, genomic studies have made much progress in investigating some of the molecular underpinnings that drive their lymphomagenesis and have paved the way for testing additional novel approaches.

Revised International Prognostic Index and genetic alterations are associated with early failure to R-CHOP in patients with diffuse large B-cell lymphoma

Relapsed or refractory diffuse large B-cell lymphoma (DLBCL) cases have a poor outcome. Here we analysed clinico-biological features in 373 DLBCL patients homogeneously treated with rituximab, cyclophosphamide, doxorubicin, vincristine and prednisolone (R-CHOP), in order to identify variables associated with early failure to treatment (EF), defined as primary refractoriness or relapse within 12 months from diagnosis. In addition to clinical features, mutational status of 106 genes was studied by targeted next-generation sequencing in 111 cases, copy number alterations in 87, and gene expression profile (GEP) in 39. Ninety-seven cases (26%) were identified as EF and showed significantly shorter overall survival (OS). Patients with B symptoms, advanced stage, high levels of serum lactate dehydrogenase (LDH) or β2-microglobulin, low lymphocyte/monocyte ratio and higher Revised International Prognostic Index (R-IPI) scores, as well as those with BCL2 rearrangements more frequently showed EF, with R-IPI being the most important in logistic regression. Mutations in NOTCH2, gains in 5p15·33 (TERT), 12q13 (CDK2), 12q14·1 (CDK4) and 12q15 (MDM2) showed predictive importance for EF independently from R-IPI. GEP studies showed that EF cases were significantly enriched in sets related to cell cycle regulation and inflammatory response, while cases in response showed over-representation of gene sets related to extra-cellular matrix and tumour microenvironment.

Defining and Treating High-grade B-cell lymphoma, NOS

High-grade B-cell lymphoma, not otherwise specified (HGBL, NOS) is a recently introduced diagnostic category for aggressive B-cell lymphomas. It includes tumors with Burkitt-like or blastoid morphology that do not have double-hit cytogenetics and that cannot be classified as other well-defined lymphoma subtypes. HBCL, NOS are rare and heterogeneous; most have germinal center B-cell phenotype, and up to 45% carry a single-hit MYC rearrangement, but otherwise they have no unifying immunophenotypic or cytogenetic characteristics. Recent analyses utilizing gene expression profiling (GEP) revealed that up to 15% of tumors currently classified as diffuse large B-cell lymphoma display a HGBL-like GEP signature, indicating a potential to significantly expand the HGBL category using more objective molecular criteria. Optimal treatment of HGBL, NOS is poorly defined due to its rarity and inconsistent diagnostic patterns. A minority of patients have early-stage disease which can be managed with standard RCHOP-based approaches with or without radiation. For advanced-stage HGBL, NOS, which often presents with aggressive, disseminated disease, high lactate dehydrogenase, and involvement of extranodal organs (including the central nervous system [CNS]), intensified Burkitt lymphoma-like regimens with CNS prophylaxis may be appropriate. However, many patients diagnosed at age > 60 years are not eligible for intensive immunochemotherapy. An improved, GEP and/or genomic-based pathologic classification that could facilitate HGBL-specific trials is needed to improve outcomes for all patients. In this review, we discuss the current clinicopathologic concept of HGBL, NOS, existing data on its prognosis and treatment, and delineate potential future taxonomy enrichments based on emerging molecular diagnostics.