non-GCB Subtype Research Articles

Value of GCET1, HGAL (GCET2), and LMO2 in the Determination of Germinal Center Phenotype in Diffuse Large B-cell Lymphoma

Diffuse large B-cell lymphoma (DLBCL) is a biologically heterogeneous disease that is classified into germinal center B-cell (GCB) and non-GCB subtypes, which are prognostically different. The Hans algorithm is the most widely used tool based on CD10, BCL6, and MUM1 expression, but some cases with the non-GCB phenotype are still known to be misclassified. In this study, we investigate the extent to which GCET1, HGAL, and LMO2 protein expressions reflect GCB phenotype together with their roles in determining the GCB phenotype of DLBCL and their contributions to the performance of the Hans algorithm. Sixty-five cases of DLBCL-not otherwise specified, 40 cases of follicular lymphoma (FL), and 19 non-GC-derived lymphoma cases were included in this study. The DLBCL cases were grouped as CD10+ (Group A) or only MUM1+ (Group B), and the remaining cases constituted the intermediate group (Group C). GCET1, HGAL, and LMO2 expressions were evaluated. In the FL group, GCET1, HGAL, and LMO2 were positive in 85%, 77.5%, and 100% of the cases, respectively. Among the non-GC-derived lymphoma cases, all three markers were negative in cases of small lymphocytic lymphoma, plasmablastic lymphoma, peripheral T-cell lymphoma, and anaplastic large cell lymphoma. GCET1 and HGAL were negative in cases of marginal zone lymphoma (MZL) and mantle cell lymphoma (MCL). Two of the 3 MZL and 2 of the 4 MCL cases were positive for LMO2. In the DLBCL group, the number of cases with GCET1, HGAL, and LMO2 positivity was 18 (90%), 17 (85%), and 20 (100%), respectively, in Group A and 0 (0%), 2 (13.3%), and 2 (13.3%), respectively, in Group B. Considering these rates, when the cases in the intermediate group were evaluated, it was concluded that 13 cases typed as non-GCB according to the Hans algorithm may have the GCB phenotype. GCET1, HGAL, and LMO2 are highly sensitive markers for determining the germinal center cell phenotype and can increase the accuracy of the subclassification of DLBCL cases, especially for cases that are negative for CD10.

Factors determining whether diffuse large B-cell lymphoma samples are detected by flow cytometry.

Flow cytometry (FCM) is widely used in the diagnosis of mature B-cell neoplasms (MBN), and FCM data are usually consistent with morphological findings. However, diffuse large B-cell lymphoma (DLBCL), a common MBN, is sometimes not detected by FCM. This study aimed to explore factors that increase the likelihood of failure to detect DLBCL by FCM. Cases with a final diagnosis of DLBCL that were analysed by eight-colour FCM were retrospectively collated. Clinical, FCM, histopathological and genetic data were compared between cases detected and cases not detected by FCM. DLBCL cases from 135 different patients were analysed, of which 22 (16%) were not detected by FCM. In samples not detected by flow cytometry, lymphocytes were a lower percentage of total events (p = 0.02), and T cells were a higher percentage of total lymphocytes (p = 0.01). Cases with high MYC protein expression on immunohistochemistry were less likely to be missed by FCM (p = 0.011). Detection of DLBCL was not different between germinal centre B-cell (GCB) and non-GCB subtypes, not significantly affected by the presence of necrosis or fibrosis, and not significantly different between biopsy specimens compared to fine-needle aspirates, or between samples from nodal compared to extranodal tissue. The study identifies several factors which affect the likelihood of DLBCL being missed by FCM. Even with eight-colour analysis, FCM fails to detect numerous cases of DLBCL.

The association of Hypoxia-Inducible Factor-2α (HIF-2α) overexpression score with Germinal Center B-Cell Like (GCB) and Non-Germinal Center B-Cell Like (Non-GCB) subtypes of Diffuse Large B-cell Lymphoma (DLBCL)

Link of Video Abstract: https://www.youtube.com/watch?v=KF58IGGdWmc Background: Diffuse large B-cell lymphoma (DLBCL) is the most common type of non-Hodgkin's lymphoma. It is classified into homogeneous subtypes, namely Germinal Center B-Cell Like (GCB) and Non-Germinal Center B-Cell Like (GCB), with the latter associated with worse survival outcomes. Increased expression of Hypoxia-Inducible Factor-2α (HIF-2α) is often observed in DLBCL and has been correlated with enhanced angiogenesis, suggesting its potential as a prognostic factor in managing DLBCL. The study evaluates the association between HIF-2α overexpression and the GCB and non-GCB subtypes of DLBCL. Methods: This cross-sectional study utilized samples from DLBCL patients at Dr. Kariadi Semarang Hospital between January and December 2021. Immunohistochemistry was performed on the samples to determine the DLBCL subtypes and assess the presence of HIF-2α. HIF-2α was evaluated by immunohistochemistry based on its distribution and intensity. The Kruskal-Wallis test was used to find the association between HIF-2α expression and the GCB and non-GCB subtypes of DLBCL. Furthermore, Spearman's rank correlation test explored the correlation between all numeric variables. Results: A total of 30 subjects were included in this study, with 7 samples of GCB subtype (23.3%) and 23 samples of non-GCB subtype (76.6%). Kruskal-Wallis test showed no association between HIF-2α expression and the subtypes of DLBCL (p=0.812). Spearman's rho correlation test indicated no correlation between HIF-2α overexpression score with NCCN IPI score in GCB (r=0.219; p=0.637) and non-GCB (r=-0.194; p=0.386). Conclusion: There was no association between HIF-2α expression and GCB and non-GCB subtypes of DLBCL. Additionally, no correlation was found between HIF-2α overexpression and NCCN IPI score.

Relationship Between Clinical Factors of Lymphoma DLBCL GCB and Non-GCB Subtype with Ki-67 Proliferation Index in Siloam Karawaci Hospital 2014 - 2018

<p><strong>Background:</strong> Non-Hodgkin large cell B-lymphoma (DLBCL: Diffuse Large B-cell Lymphoma) were classified into two subtypes of Germinal Center B-Cell Like (GCB) and non-Germinal Center B-Cell Like (non-GCB), which GCB has a better prognosis. The Ki-67 antigen is one of the most reliable markers of cell proliferation. This research aims to establish the relationship between proliferation index Ki-67 with DLBCL subtypes and to evaluate the utility of Ki-67 proliferative index as a predictive marker for predicting stages of lymphoma.</p><p><strong>Methods: </strong>We obtained 60 cases of patient samples DLBCL in Siloam Hospital Lippo Karawaci in 2014-2018. Clinical and pathological data were obtained from medical records. Chi-square methods were used to analyze data.</p><p><strong>Result:</strong> There were more ≤60 years compared to >60 years. In this study, there were more male patients than female patients. lymphoma provided in extranodal were higher than lymphoma in nodal form.</p><p><strong>Conclusions:</strong> There is a relationship between Ki-67 proliferation index with lymphoma GCB and non-GCB subtypes and stage of lymphoma, which can be used as a predictive factor in predicting the stage of lymphoma.</p>

17th International Conference on Malignant Lymphoma, Palazzo dei Congressi, Lugano, Switzerland, 13 - 17 June, 2023.

Background: R-CHOP immunochemotherapy is the first-line treatment for DLBCL, but approximately 30%–40% of patients still experience refractory or relapsed (R/R) disease. We aimed to characterize the molecular features of DLBCL derived from patients with early R/R disease and develop a prognosis model to identify those high-risk patients. Methods: We performed a comprehensive genomic and transcriptomic characterization on 161 R-CHOP-treated DLBCL samples. These patients were grouped by follow-up outcome status after R-CHOP treatment. The first group had R/R disease within two years of diagnosis (poor outcome; n = 50), and the second group remained in remission at two years following R-CHOP treatment (good outcome; n = 111). In an addition, external cohorts were included in the validation analysis (GSE117556, n = 374; GSE181063, n = 810). Results: Patients with poor outcomes more often had an advanced stage of the disease, a high international prognostic index (IPI) and a non-GCB subtype of the tumor. We identified a set of frequent somatically mutated targets (Figure 1A), including PIM1, TP53, MPEG1 and ROBO1, as well as a specific mutational signature (activation-induced cytidine deaminase related) in DLBCLs with poor outcomes. Transcriptomic analyses further showed a distinct gene expression pattern and a less inflamed tumor microenvironment in these patients (Figure 1B). Finally, we developed an 11-gene signature as an independent prognostic marker for DLBCL patients treated with R-CHOP (Figure 1C). The 11-gene signature could further stratify DLBCL patients based on their IPI scores (Figure 1D). Additionally, the use of 11-gene signature to identify high-risk patients was also validated in two independent cohorts, suggesting the robustness of the risk model. Furthermore, our model effectively identified high-risk patients, including those with double-hit and MCD genetic subtypes that are associated with poor survival outcomes. FIGURE 1 (A) The mutation pattern between poor outcome and good outcome DLBCLs. (B) Tumor-infiltrating immune cells in DLBCL patients with poor and good outcomes. (C-D) Kaplan–Meier survival analysis of PFS between high-risk and low-risk groups (C) and the association of 11-gene risk scores and IPI risk groups (D). Keywords: Aggressive B-cell non-Hodgkin lymphoma, Diagnostic and Prognostic Biomarkers, Genomics, Epigenomics, and Other -Omics No conflicts of interests pertinent to the abstract.

17th International Conference on Malignant Lymphoma, Palazzo dei Congressi, Lugano, Switzerland, 13 - 17 June, 2023.

Large B-cell lymphoma (LBCL) is the most common lymphoma worldwide. About 40% of patients relapse, and most are not eligible for transplantation due to chemoresistant disease, advanced age, comorbidities, or lack of access to tertiary care. Similarly, CAR-T remains inaccessible for the majority of patients due to poor fitness, aggressive disease, lack of social support, to name a few. Thus, R/R LBCL is an area of great unmet need, with median survival measuring <1 yr. Recently, several less intensive regimens designed for outpatient administration have been approved in the United States. Tafasitamab-lenalidomide is a promising regimen, with durable remissions comparable even to CAR T-cell in some analyses. We hypothesize that if tafa-len is a well-tolerated and effective backbone, then the addition of biologically targeted agents could lead to improved outcomes while limiting toxicity. The SWOG 2207 trial will test the addition of tazemetostat or zanubrutinib to the tafa-len backbone in a randomized study open nationwide. Furthermore, we will evaluate the impact of cell-of-origin (COO) on efficacy. Following a safety run-in of 12 patients per each experimental arm, the randomized Phase II study will enroll 180 patients to Arm 1: tafa-len + tazemetostat; Arm 2: tafa-len (control); or Arm 3: tafa-len + zanubrutinib (Figure 1). The primary objective of the phase II portion is to compare the PFS of patients treated on the experimental arms with the control. Secondary objectives will include estimating hazard ratios for PFS based on GCB and non-GCB subtypes for each experimental treatment arm. Other objectives will include exploring PFS by molecular profile and genetic subtypes. Frailty and its correlation to outcome will be assessed. In addition, patient-reported lymphoma specific symptoms by PRO-CTCAE will be measured, as well as, quality of life using the FACT-Lym, and will be compared between arms. The research was funded by: NIH/NCI/NCTN grants U10CA180888/U10CA180819 Keywords: aggressive B-cell non-Hodgkin lymphoma, molecular targeted therapies, ongoing trials No conflicts of interests pertinent to the abstract.

Myc rearrangement and concurrent high protein expression of C-Myc/Bcl2 carry an adverse prognosis in diffuse large B-cell lymphoma

PurposeDiffuse large B-cell lymphoma (DLBCL) is a heterogeneous group of non-Hodgkin lymphoma, characterized by a variety of clinicopathological, histomorphological, immunophenotypic, and molecular genetic features. The subtype of DLBCL known as double-expressor lymphoma (DEL) is associated with an adverse prognosis when treated with R-CHOP. Our study aimed to investigate the clinicopathologic features of DEL and the prognostic roles of Myc rearrangement and C-Myc expression in DEL patients. Patients and methodsWe conducted a retrospective study of 145 patients who were identified through fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC) testing. ResultsWe found that DEL patients were more likely to have a non-germinal center B-cell (GCB) subtype, stage III/IV disease, and a high International Prognostic Index (IPI) score. Our survival analysis indicated that Myc rearrangement and C-Myc expression were associated with poor prognosis. Although DEL patients with Myc rearrangement exhibited trends towards worse survival compared with patients without Myc rearrangement, the differences were not statistically significant (P = 0.4008). The median overall survival (OS) of DEL patients with ≥70 % C-Myc expression (DEL-C-Mychigh) was 5 months. In the DEL-C-Mychigh group, the non-GCB subtype showed nonsignificant trends towards poorer survival compared with the GCB subtype (P = 0.1042). ConclusionIn conclusion, our study shows that a cut-off of ≥70 % for C-Myc expression in DEL patients can improve risk stratification, and suggests that more intensive treatment regimens may be necessary to improve survival in this high-risk population.

MYD88L265P and MYD88other variants show different molecular characteristics and prognostic significance in diffuse large B-cell lymphoma.

This study aims to investigate the clinical and molecular differences between diffuse large B-cell lymphoma (DLBCL) patients with MYD88L265P and MYD88other. DLBCL patients with MYD88 variations were collected from the Cancer Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College (CHCAMS), and Suzhou Municipal Hospital from February 6th, 2007 to May 20th, 2022. Clinicopathological parameters and treatment outcomes between MYD88L265P and MYD88other were investigated. A total of 132 patients with MYD88 variations from a cohort of 475 DLBCL patients were included, among which, 78 were MYD88L265P, while 54 were MYD88other. MYD88L265P was more common in non-GCB subtype than MYD88other (83% vs. 60%, P = 0.004). Besides, MYD88L265P was significantly related to higher proportion of testicle/ central nervous system involvement (31% vs. 6%, P < 0.001), PIM1 mutation (71% vs. 39%, P < 0.001), and PIM1 hypermutation (28% vs. 11%, P = 0.018), compared with MYD88other. Compared with MYD88L265P, MYD88other were more likely to have higher percentage of advanced stage (60% vs. 42%, P = 0.044), extranodal site ≥ 2 (45% vs. 28%, P = 0.044), elevated LDH (55% vs. 35%, P = 0.033), positive CD10 expression (36% vs. 16%, P = 0.009), BCL-6 translocation (20% vs. 8%, P = 0.033), and NOTCH pathway gene alteration (24% vs. 13%, P = 0.040). In non-GCB DLBCL subtype, patients with MYD88other were significantly associated with worse progression free survival (PFS) than those with MYD88L265P when treated initially with R-CHOP/R-CHOP-like regimen (P = 0.010). The findings of this study indicate that DLBCL patients with MYD88L265P and MYD88other are likely to be two subgroups with different clinical and molecular characteristics. The survival of patients with MYD88other is not superior than those with MYD88L265P, even poorer when focusing on the non-GCB subtype.

Salinomycin sodium exerts anti diffuse large B-cell lymphoma activity through inhibition of LRP6-mediated Wnt/β-catenin and mTORC1 signaling

Low-density lipoprotein receptor-related protein-6 (LRP6) is overexpressed in various cancers. The small molecule salinomycin sodium inhibits LRP6. We observed a higher proportion of subjects with non-germinal center B (non-GCB) subtypes having high LRP6 expression than those with GCB subtypes by immunohistochemistry. The PCR and Western blot assays demonstrated increased LRP6 expression in non-GCB subtype cells. In addition, CCK-8 assays and transwell cell migration assays revealed that salinomycin sodium exhibited dose- and time-dependent inhibition of proliferation and migration in non-GCB subtype cells. Furthermore, Western blot assays showed that salinomycin sodium decreased the expression of Bcl2, while increasing the expression of Bax. Additionally, salinomycin sodium suppressed LRP6 expression, blocked LRP6 phosphorylation, and inhibited the Wnt/β-catenin and mTORC1 signaling pathways. Our results suggest that LRP6 is highly expressed in non-GCB subtype. Furthermore, salinomycin sodium inhibited LRP6 expression and the Wnt/β-catenin and mTORC1 signaling in non-GCB subtype cells, and displayed potent anticancer activity.

Abstract 6156: MALT1 protease inhibition overcomes BTK inhibitor resistance and shows synergistic activity with venetoclax in models of B cell lymphoma and leukemia

Abstract Introduction: Specific B cell malignancies, including CLL and the aggressive non-GCB subtype of DLBCL, are driven by constitutive activation of the B cell receptor (BCR) pathway and the transcription factor NF-κB. Pharmacological inhibition of MALT1 protease, a key mediator of the BCR/NF-κB signal transduction pathway, may therefore provide an attractive treatment option for patients with these cancers. Further, as combination therapy is often required for the treatment of aggressive B cell malignancies, the identification of therapies that synergistically combine with MALT1 inhibitors could afford additional and promising treatment options. Experimental Procedures: A highly potent and orally bioavailable MALT1 protease inhibitor (ABBV-MALT1) was used to test the hypothesis that MALT1 inhibition will abrogate the proliferation of preclinical models of B cell malignancies in vitro and in vivo. Tumors treated with ABBV-MALT1 were subjected to transcriptomic and functional proteomic assays to elucidate molecular mechanisms of action and rational combination partners. Results: Mechanistic studies reveal that ABBV-MALT1 effectively inhibits signal transduction of the BCR pathway and reduces NF-κB gene activation in non-GCB DLBCL cell lines resulting in cell cycle arrest and diminished viability. In vivo, oral administration of this compound demonstrates robust tumor growth inhibition in several models of B cell tumors, including non-GCB DLBCL models that are resistant to Bruton’s tyrosine kinase (BTK) inhibitors. NF-κB target genes include the pro-survival family members BCL-XL and BCL2-A1, which aid in regulation of the intrinsic apoptosis pathway. As ABBV-MALT1-induced inhibition of the NF-κB pathway resulted in downregulation of these genes, we hypothesized that the associated tumor models would become increasingly dependent on the pro-survival family member BCL-2. To test this hypothesis, combination studies of ABBV-MALT1 and the selective BCL-2 inhibitor venetoclax were performed in both cell line and patient-derived xenograft models of DLBCL. Herein we show that concomitant administration of ABBV-MALT1 and venetoclax results in dramatic antitumor activity in all models tested in vivo. This efficacy also translates to primary patient CLL cells in vitro where the combination confers greater levels of apoptosis compared to either agent alone. Conclusion: ABBV-MALT1 demonstrates robust single agent anti-tumor activity in malignant B cell models that are resistant to BTK inhibitors. Moreover, combination of ABBV-MALT1 with the BCL-2 inhibitor venetoclax shows synergistic cell killing of B cell tumors in vitro and dramatic tumor regression in vivo. Together, these data indicate that MALT1 inhibition may overcome BTK inhibitor resistance and combine with venetoclax to effectively treat patients with B cell malignancies. Citation Format: Joshua P. Plotnik, Raghuveer S. Mali, Velitchka Bontcheva, Colleen Dowell, Jun Chen, Adam E. Richardson, Ryan A. McClure, Paul Jung, Lan Pham, Andrew J. Souers, Jonathan A. Meulbroek, William N. Pappano. MALT1 protease inhibition overcomes BTK inhibitor resistance and shows synergistic activity with venetoclax in models of B cell lymphoma and leukemia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6156.

High density of FOXP3 predicts better prognosis in germinal and non-germinal centre diffuse large B-cell lymphoma.

This study highlights the prognostic impact of FOXP3 and CD68 expression in DLBCL, NOS and in its GCB and non-GCB subtypes. This may help the development of individualized therapy, prognostic prediction and therapy stratification.

Non-germinal center B-cell subtype of pediatric diffuse large B-cell lymphoma in Japan: A retrospective cohort study.

Diffuse large B-cell lymphoma (DLBCL) is classified into two molecular subtypes according to its cell of origin: germinal center B-cell (GCB) subtype and activated B-cell/non-GCB subtype. This latter subtype shows a poorer prognosis in adults. However, in pediatric DLBCL, the prognostic impact of the subtype is yet to be clarified. This study sought to compare the prognosis between GCB and non-GCB DLBCL in a large number of cases in children and adolescents. In addition, this study intended to describe the clinical, immunohistochemical, and cytogenetic characteristics of these two molecular subtypes of DLBCL, and consider differences in the biology, frequency, and prognosis of GCB and non-GCB subtypes in pediatric versus adult DLBCL or in Japanese versus Western pediatric DLBCL patients. We selected mature B-cell lymphoma/leukemia patients for whom specimens had been submitted to the central pathology review in Japan between June 2005 and November 2019. We referred the past studies on Asian adult patients and Western pediatric patients to compare with our results. Data were obtained from 199 DLBCL patients. The median age of all patients was 10years, with 125 patients (62.8%) in the GCB group and 49 (24.6%) in the non-GCB group other than 25 cases whose immunohistochemical data were insufficient. Overall, the percentage of translocation of MYC (1.4%) and BCL6 (6.3%) was lower than in adult and Western pediatric DLBCL cases. The non-GCB group showed a significantly higher proportion of females (44.9%), a higher incidence of stage III disease (38.8%), and B-cell lymphoma 2 (BCL2)-positivity in immunohistochemistry (79.6%) compared to the GCB group; however, no BCL2 rearrangement was observed in both GCB and non-GCB groups. The prognosis did not differ significantly between the GCB and non-GCB groups. This study including a large number of non-GCB patients showed the same prognosis between GCB and non-GCB groups and suggested a difference in the biology of pediatric and adolescent DLBCL compared to adult DLBCL as well as between Asian and Western DLBCL.

Clinical Characteristics and Prognosis of Patients with Primary Testicular Diffuse Large B-Cell Lymphoma

To analyze the clinical manifestations, therapeutic response and prognosis of patients with primary testicular diffuse large B-cell lymphoma (PT-DLBCL). Thirty-eight patients with PT-DLBCL were enrolled, who hospitalized from January 2010 to April 2021, and their clinical characteristics, treatment regimen and efficacy were collected and analyzed retrospectively. The median age of the patients was 56 years old (ranged from 38 to 79 years). There were 4 cases (10.5%) with bilateral lesions, 13 cases (34.2%) with left lesions, and 21 cases (55.3%) right lesions. There were 2 cases(5.3%) with B symptoms, 6 cases (15.8%) of germinal center B-cell-like(GCB) subtype and 32 cases(84.2%) of non-GCB subtype. Efficacy was evaluated in 36 cases, including 10 cases with CHOP regimen, 21 cases with R-CHOP regimen (7 cases were treated with rituximab combined with high-dose methotrexate injection chemotherapy at intervals of R-CHOP regimen), and 5 cases with other regimens. In 36 patients, the efficacy evaluation of initial chemotherapy showed that the overall response rate (ORR) was 86.1%, 29 cases (80.6%) reached complete response (CR), and 2 cases (5.5%) reached partial response (PR). The R-CHOP group was superior to CHOP group in ORR (95.2% vs 60.0%, P=0.027) and CR (90.4% vs 50.0%, P=0.022). Of the 36 patients, 7 cases had central nervous system(CNS) recurrence and 4 cases had contralateral testicular recurrence. Compared with the CHOP group, the CNS recurrence rate in the R-CHOP group was significantly lower (4.8% vs 50.0%, P=0.007), and the testicular recurrence rate in the R-CHOP group was also lower than the CHOP group, but the difference was not statistically significant (4.8% vs 30.0%, P=0.087). The median follow-up time was 27(3-135) months, and the 5-year PFS and OS were 71% and 74%, respectively. Kaplan-Meier univariate analysis showed that the R-CHOP regimen significantly improved the patients' PFS (P=0.024) and OS (P=0.025) compared with the CHOP regimen. PT-DLBCL is mainly treated with comprehensive treatment. Compared with CHOP regimen, R-CHOP regimen can improve the CR rate and ORR, reduce CNS recurrence and contralateral testicular recurrence, and improve the patients' survival. Patients may benefit from high-dose methotrexate combined with rituximab interlaced with R-CHOP regimen.

Genomic Profiling Reveals Differences in Primary Central Nervous System Lymphoma and Large B-Cell Lymphoma, With Subtyping Suggesting Sensitivity to BTK Inhibition.

B-cell primary central nervous system (CNS) lymphoma (PCL) is diffuse large B-cell lymphoma (DLBCL) confined to the CNS. Less than 50% of patients with PCL achieve complete remission with current therapies. We describe the findings from comprehensive genomic profiling (CGP) of a cohort of 69 patients with PCL, 36 cases of secondary CNS lymphoma (SCL), and 969 cases of DLBCL to highlight their differences and characterize the PCL cohort. In addition, we highlight the differences in frequency of germinal center B-cell like (GCB) and non-GCB subtypes and molecular subtypes, particularly MCD and EZH subtypes, between PCL and DLBCL. Sixty-nine cases of B-cell PCL, 36 cases of secondary CNS lymphoma (SCL), and 969 cases of DLBCL were evaluated by CGP of 405 genes via DNAseq and 265 genes via RNAseq for fusions (FoundationOne Heme). Tumor mutational burden (TMB) was calculated from 1.23 Mb of sequenced DNA. Genomic alterations with significant differences between PCL and DLBCL included MYD88, ETV6, PIM1, PRDM1, CXCR4, TP53, and CREBBP, while only MYD88 was significantly different between SCL and DLBCL. PCL cases were significantly enriched for the MCD molecular subtypes, which have an excellent response to BTKi. We report a patient with a durable complete response to BTKi consistent with their genomic profile. EBV status, CD274 amplification, and TMB status suggest that 38% of PCL patients may benefit from ICPI; however further study is warranted. CGP of PCLs reveals biomarkers, genomic alterations, and molecular classifications predictive of BTKi efficacy and potential ICPI efficacy. Given the limitations of standard of care for PCL, CGP is critical to identify potential therapeutic approaches for patients in this rare form of lymphoma.

Programmed death-ligand 1 expression in diffuse large B-cell lymphoma is associated with poor prognosis.

Programmed death-ligand 1 (PD-L1) expression in some tumors has prognostic implications. This work aims at investigating PD-L1 expression in diffuse large B-cell lymphoma (DLBCL) and to study its association with clinicopathological variables. The study consisted of 75 DLBCL patients who were cared for at the King Hussein Cancer Center during the period 2015-2018. The expression of PD-L1 in tumor tissue was assessed by immunohistochemistry using the anti-human PD-L1 (Clone 22C3) monoclonal antibody. The correlation between gender, age, clinical stage, pre-treatment-LDH level, tumor location, response to therapy, overall and event-free survival with PD-L1 expression was studied. Six patients were excluded from further analysis as they were in relapse at the time of tissue sampling. The tumor proportion score (TPS) was ≥1% in 16/69 (23.2%) of DLBCL cases while the combined positive score (CPS) at a cut-off of ≥20 was observed in 23/69 (33.3%) cases. No significant difference in PD-L1 expression was found between germinal center B-cell-like (GCB) and non-GCB subtypes. Similarly, no differences in PD-L1 expression (at CPS ≥20 and TPS ≥1) were found between different genders, age groups, clinical stages, tumor location, and patient response to therapy. However, base-line lactate dehydrogenase was significantly elevated in patients with PD-L1 CPS ≥20. The overall survival was not significantly different between PD-L1-positive and -negative groups. On the other hand, the median event-free survival was higher in either of the PD-L1 TPS or CPS negative groups at 107months each versus 54 months in the PD-L1 positive group of either category. PD-L1 expression can predict event-free survival in DLBCL cases and therefore poor prognosis.

Inhibition of CD39 unleashes macrophage antibody-dependent cellular phagocytosis against B-cell lymphoma.

Redirection of tumor-associated macrophages to eliminate tumor cells holds great promise for overcoming therapeutic resistance to rituximab and other antibody drugs. Here, we determined the expression of ectonucleotidases CD39 and CD73 in diffuse large B-cell lymphoma (DLBCL), and examined the impact of extracellular ATP (eATP) metabolism on macrophage-mediated anti-lymphoma immunity. Immunostaining of tissue microarray samples showed that CD39 (the ecto-enzyme for eATP hydrolysis) was highly expressed in tumors with the non-germinal center B-cell-like (non-GCB) subtype, and to a lesser extent tumors with the GCB subtype. By contrast, the expression of CD73 (the ecto-enzyme for adenosine generation) was undetectable in tumor cells. Pharmacological blockade of CD39 prevented eATP degradation and enhanced engulfment of antibody-coated lymphoma cells by macrophages in a P2X7 receptor-dependent manner, indicating that eATP fueled antibody-dependent cellular phagocytosis (ADCP) activity. Importantly, inhibition of CD39 augmented in vivo anti-lymphoma effects by therapeutic antibodies including rituximab and daratumumab. Furthermore, the addition of a CD39 inhibitor to anti-CD20 and anti-CD47 combination therapy significantly improved survival in a disseminated model of aggressive B-cell lymphoma, supporting the benefit of dual targeting CD39-mediated eATP hydrolysis and CD47-mediated "don't eat me" signal. Together, preventing eATP degradation may be a potential approach to unleash macrophage-mediated anti-lymphoma immunity.

SHP1 loss augments DLBCL cellular response to ibrutinib: a candidate predictive biomarker.

SHP1, a tyrosine phosphatase, negatively regulates B-cell receptor (BCR) signaling. Ibrutinib selectively inhibits BTK and has been approved for the treatment of several types of B-cell lymphomas, but not yet in diffuse large B-cell lymphoma (DLBCL). A phase 3 clinical trial of ibrutinib-containing regimen has been completed to evaluate its activity in subtypes or subsets of DLBCL patients. Although the subtype of activated B-cell like (ABC) DLBCL is characterized by chronic active BCR signaling, only a fraction of ABC-DLBCL patients seem to benefit from ibrutinib-containing regimen. New alternative predictive biomarkers are needed to identify patients who better respond. We investigated if SHP1 plays a role in defining the level of the BCR activity and impacts the response to ibrutinib. A meta-analysis revealed that lack of SHP1 protein expression as well as SHP1 promoter hypermethylation is strongly associated with NHL including DLBCL. On a tissue microarray of 95 DLBCL samples, no substantial difference in SHP1 expression was found between the GCB and non-GCB subtypes of DLBCL. However, we identified a strong reverse correlation between SHP1 expression and promoter methylation suggesting that promoter hypermethylation is responsible for SHP1 loss. SHP1 knockout in BCR-dependent GCB and ABC cell lines increased BCR signaling activities and sensitize lymphoma cells to the action of ibrutinib. Rescue of SHP1 in the knockout clones, on the other hand, restored BCR signaling and ibrutinib resistance. Further, pharmacological inhibition of SHP1 in both cell lines and patient-derived primary cells demonstrate that SHP1 inhibition synergized with ibrutinib in suppressing tumor cell growth. Thus, SHP1 loss may serve as an alternative biomarker to cell-of-origin to identify patients who potentially benefit from ibrutinib treatment. Our results further suggest that reducing SHP1 pharmacologically may represent a new strategy to augment tumor response to BCR-directed therapies. Schematic diagram summarizing the major findings. Left panel. When SHP1 is present and functional, it negatively regulates the activity of the BCR pathway. Right pane. When SHP1 is diminished or lost, cells depend more on the increased BCR signaling and making them vulnerable to BTK inhibitor, ibrutinib. Diagram was generated using BioRender.

Circulating tumor DNA mutation profile is associated with the prognosis and treatment response of Chinese patients with newly diagnosed diffuse large B-cell lymphoma

Characterization of gene mutation profiles can provide new treatment options for patients with diffuse large B-cell lymphoma (DLBCL). However, this method is challenged by the limited source of tissue specimens, especially those of DLBCL patients at advanced stages. Therefore, in the current study, we aimed to describe the gene mutation landscape of DLBCL using circulating tumor DNA (ctDNA) samples obtained from patients' blood samples, as well as to explore the relationship between ctDNA mutations and the prognosis and treatment response of patients with newly diagnosed DLBCL. A total of 169 newly diagnosed Chinese DLBCL patients were included in this study, among which 85 patients were divided into a training set and 84 were assigned into a validation set. The mutation profile of a 59-gene panel was analyzed by targeted next generation sequencing (NGS) of the patients' ctDNA samples. Differences in clinical factors between patients with and without ctDNA mutations were analyzed. In addition, we also explored gene mutation frequencies between GCB and non-GCB subtypes, and the relationship between gene mutation status, clinical factors, mean VAF (variant allele frequencies) and the patients' overall survival (OS) and progression-free survival (PFS). ctDNA mutations were detected in 64 (75.3%) patients of the training set and 67 (79.8%) patients of the validation set. The most commonly mutated genes in both sets were PCLO, PIM1, MYD88, TP53, KMT2D, CD79B, HIST1H1E and LRP1B, with mutation frequencies of >10%. Patients with detectable ctDNA mutations trended to present advanced Ann Arbor stages (III-IV), elevated LDH (lactate dehydrogenase) levels, shorter OS and PFS, and a lower complete response (CR) rate to the R-CHOP regimen compared with DLBCL patients without ctDNA mutations. In addition, mean VAF (≥4.94%) and PCLO mutations were associated with poor OS and PFS. We investigated the ctDNA mutation landscape in Chinese patients with newly diagnosed DLBCL and found that ctDNA could reflect tumor burden and patients with detectable ctDNA mutations trended to have shorter OS and PFS and a lower CR rate.

Orelabrutinib in Combination with Rituximab and Chemotherapy for Newly Diagnosed Aggressive B-Cell Lymphoma: A Multicenter, Single-Arm, Prospective Study

Keywords: Orelabrutinib, B-cell lymphoma, overall response rate Introduction Dysregulated B-cell receptor (BCR) signaling has been identified as an important feature of B-cell lymphomas. Inhibition of Bruton's tyrosine kinase (BTK), downstream of BCR, has demonstrated promising efficacy profiles in B-cell malignancies. Orelabrutinib is a newly developed BTK inhibitor with high selectivity for B-cell malignancies. This study was conducted to evaluate the preliminary efficacy and safety of orelabrutinib in combination with rituximab and chemotherapy for newly diagnosed aggressive B-cell lymphoma. Methods This was a single-arm, multicenter, prospective study in patients with clinical and histopathological confirmed aggressive B-cell lymphoma. The primary endpoints were investigator-assessed overall response rate (ORR) and complete response (CR) rate. Adverse events (AEs) were assessed in accordance with NCI CTCAE v4.03. Results A total of 42 patients with newly diagnosed aggressive B-cell lymphoma were enrolled from October 2020 to May 2022, including 28 diffuse large B-cell lymphoma (DLBCL), 12 primary central nervous system lymphoma (PCNSL), and 2 patients with high-grade B-cell lymphoma. The median age was 66.5 years (range, 35-86 years), and 23 (54.7%) were male. 66.7% of enrolled patients had stage III-IV disease. The median follow-up was 8.0 months (2.0-20.0 months). All the patients received orelabrutinib combined with rituximab and chemotherapy regimens. At data cutoff, 28 patients completed 6 cycles of treatment and were evaluated for therapeutic efficacy. Next-generation sequencing was performed and the genetic mutations included MYD88, BCL6, BCL2, CD79b, KMT2D, etc. All 42 patients were evaluable for toxicity. The toxic reactions were relatively mild, including grade 3 febrile neutropenia in 2 cases (4.8%), grade 3 neutropenia (2.4%), grade 3 thrombocytopenia (2.4%), and grade 3 leukopenia (2.4%). No other grade 3-4 non-hematologic AEs were reported. There was no dose modification due to AEs. The therapeutic responses were assessed. Among the 30 patients with DLBCL or high-grade B-cell lymphoma, 21 patients completed 6 cycles of treatment at data cutoff, with an ORR of 100%, and 15 (71.4%) patients achieved CR. The estimated 1-year overall survival (OS) and 1-year progression-free survival (PFS) rates were 100% and 94.1%, respectively. In addition, subgroup analyses were performed. Seventeen patients were non-GCB subtype, with a CR rate of 84.5%. Among the included DLBCL patients, 13 patients had MYC/BCL2 protein dual expression (DE), and the ORR and CR rate were 100% and 90.9%, respectively. Twenty-two patients were extra-nodal DLBCL, with a CR rate of 86.7%. The estimated 1-year PFS rate was 93.8%. Among them, 13 patients were non-GCB subtype, and 11 of them received 6 courses of treatment, with a CR rate of 81.8%. We further analyzed the treatment response of PCNSL patients. A total of 12 patients with newly diagnosed PCNSL were included in this study, with a median age of 57 years (range, 35-75 years) and 7 (58.2%) patients were male. Ten (83.3%) patients were non-GCB subtype. Seven patients completed 6 courses of treatment, with an ORR of 100%, and 4 patients achieved CR. Conclusions The preliminary results of this study suggested that orelabrutinib in combination with rituximab and chemotherapy may be a well-tolerated and effective regimen in newly diagnosed aggressive B-cell lymphoma patients. A larger sample size and longer follow-up time are needed in the future to validate this conclusion. Next-generation sequencing results are expected to provide additional explanations for differential treatment responses. Disclosure: No relevant conflicts of interest to declare.

Outcomes with Immunochemotherapy Plus Radiation Versus Immunochemotherapy Alone in Stage I Diffuse Large B-Cell Lymphoma: A Retrospective Study

Introduction Diffuse Large B-cell lymphoma (DLBCL) is the most common subtype of non-Hodgkin lymphoma with a prognosis highly dependent on the stage of the disease. The mainstay of front-line therapy for limited-stage DLBCL is R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone) or R-CHOP-like immunochemotherapy (IC). The impact of combined modality therapy (CMT) with radiation therapy (RT) after IC remains uncertain in the rituximab era. In the pre-rituximab era, studies comparing the efficacy of chemotherapy with or without RT showed heterogenous results. To date, only a few single institutional studies have compared IC versus CMT. The aim of this study is to evaluate the efficacy of standard IC compared to CMT in patients with stage I DLBCL in the rituximab era. Methods Adult patients with stage I DLBCL diagnosed between 2002 to 2015 and seen at Mayo Clinic Rochester were identified. Data were obtained from medical records. All patients were treated with IC (R-CHOP or R-CHOP-like), or IC followed by radiation (CMT). The student's t-test or the Wilcoxon rank-sum test was used to analyze between-group differences, as appropriate. Chi-square or Fisher's exact test was used for categorical variable comparisons. Progression-free survival (PFS) was defined as the time from the date of diagnosis to the date of relapse, death or the date of the last follow-up and was analyzed using the Kaplan-Meier method. Overall survival (OS) was defined as the time from the date of diagnosis to the date of last follow-up or death. Response to treatment was evaluated by treating physicians. Results The study included 123 patients diagnosed with stage I DLBCL with a median follow-up time of 65.9 months for IC arm and 56.2 months for CMT arm. Overall, 78 patients were treated with six cycles of IC, and 45 patients were treated with 2-4 cycles of IC followed by involved-site radiation (2 cycles in 4 patients, 3 cycles in 25 patients, 4 cycles in 16 patients). There were no significant differences in age, sex, or extranodal involvement. In the IC group, 59 patients had cell of origin data available: 44 (56.41%) were GCB subtype and 15 patients (19.23%) were non-GCB subtype. In the CMT group, 21 patients (47%) and 9 patients (20%) had GCB and non-GCB subtypes, respectively. Double-hit lymphoma (defined as rearrangement of MYC together with rearrangement of BCL2 and/or BCL6) was reported in 4 out of 78 patients in the IC arm and 2 out of 45 patients in the CMT arm. There was no significant difference in response rates to frontline treatment between groups. In the IC group, the overall response rate (ORR) was 92% (n=72), and the rate of complete response (CR) was 87% (n=68), partial response (PR) was 5% (N=4), stable disease (SD) was 5% (n=4), and progressive disease (PD) was 5% (n=4). In the CMT group, the ORR was 96% (n=43, all CR); 2 patients achieved SD (4%) and no patients had a PR or PD. With a median follow-up time of 65.9 months for IC arm, 14 patients had died. With a median follow-up of 56.2 months for the CMT arm, 14 patients had died. Median PFS was not reached in the IC group while PFS was more than 10 years in the CMT group (p=0.7851) [Figure 1]. There was no significant OS difference observed in both groups (p=0.2561) [Figure 2]. Conclusion Our study showed no significant difference in OS and PFS between patients with stage I DLBCL treated with IC or CMT. Future research on a larger patient population is needed to evaluate the role of consolidation radiotherapy in early stage DLBCL. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal