Diagnosis Of Follicular Lymphoma Research Articles

Utility of MEF2B Immunohistochemistry in Distinguishing Follicular Lymphoma and Marginal Zone Lymphoma in Diagnostically Challenging Cases

Abstract Introduction/Objective Distinguishing follicular lymphoma (FL) from marginal zone lymphoma (MZL) can be challenging, as the morphology and immunophenotype can overlap particularly in CD10-negative cases or those with marginal zone differentiation (MZD). MEF2B (Myocyte enhancer binding factor B) is a transcription factor that controls BCL6 expression in germinal center (GC) B-cells. Previous studies report MEF2B to have a high sensitivity and specificity for FL compared to other GC markers. We investigated the expression of MEF2B in low grade B cell lymphomas (LGBCL) to evaluate its utility in classifying diagnostically challenging cases and FL with MZD. Methods/Case Report Our archives were searched from 2005-2023 to identify excisional biopsies of LGBCL with MZD, including (FL), splenic MZL (SMZL), MZL of mucosa-associated lymphoid tissue (MALT), nodal MZL (NMZL) and difficult-to-classify (DTC) cases with a differential diagnosis of MZL and FL. MEF2B immunohistochemistry was performed retrospectively (Atlas Antibodies). Two hematopathologists assigned a pre-and post-MEF2B diagnosis to DTC cases. Results (if a Case Study enter NA) 57 cases were included: 21 FL (12 with MZD), 11 SMZL, 13 MALT, 4 NMZL, and 8 DTC cases. 19/21 FL cases (90%) were positive for MEF2B, including 11/12 (92%) cases with MZD. However, MEF2B expression was restricted to the follicles and negative in MZD areas in 7/11 cases (64%), while 4 cases showed partial weak expression in the areas of MZD. 0/11 SMZL (0%), 0/13 MALT (0%), and 0/4 (0%) NMZL were positive for MEF2B. 6/8 DTC cases (75%) were positive for MEF2B. Within DTC cases, retrospective inclusion of MEF2B results helped to render a more definitive diagnosis in 5 cases (2 negative/3 positive). Conclusion MEF2B immunohistochemistry can aid in distinguishing FL from MZL in challenging cases. However, it is often negative in areas of FL with MZD so care must be taken on interpretation in small biopsies.

Proteomic Profiling Identifies Predictive Signatures for Progression Risk in Patients with Advanced-Stage Follicular Lymphoma.

Background: Follicular lymphoma (FL) is characterized by an indolent nature and generally favorable prognosis, yet poses a particular clinical challenge, since disease progression is observed in a notable subset of patients. Currently, it is not possible to anticipate which patients will be at risk of progression, highlighting the need for reliable predictive biomarkers that can be detected early in the disease. Methods: We applied tandem-mass-tag labelled nano-liquid chromatography tandem mass spectrometry (nLC-MS/MS) on 48 diagnostic formalin-fixed, paraffin-embedded tumor samples from patients with advanced-stage FL. Of these, 17 experienced subsequent progression (subsequently-progressing, sp-FL) while 31 did not (non-progressing, np-FL). Results: We identified 99 proteins that were significantly differentially expressed between sp-FL samples and np-FL samples (p < 0.05; log2-fold changes between 0.2 and -1.3). Based on this subset of proteins, we classified patients into high-risk and low-risk subgroups using unsupervised machine learning techniques. Pathway analyses of the identified proteins revealed aberrancies within the immune system and cellular energy metabolism. In addition, two proteins were selected for immunohistochemical evaluation, namely stimulator of interferon genes 1 (STING1) and isocitrate dehydrogenase 2 (IDH2). Notably, IDH2 retained significantly lower expression levels in sp-FL samples compared with np-FL samples (p = 0.034). Low IDH2 expression correlated with shorter progression-free survival (PFS, p = 0.020). Conclusions: This study provides evidence for some of the biological mechanisms likely to be involved in FL progression and, importantly, identifies potential predictive biomarkers for improvement of risk stratification up-front at time of FL diagnosis.

Abstract PR03: Immunosurveillance of precancerous germinal center B cells

Abstract Most Non-Hodgkin Lymphomas (NHLs) originate from germinal center (GC) or post-GCB cells. While the immune system actively targets precancerous cells in epithelial-derived cancers, it is uncertain if the same applies to precancerous GCB cells. Knowledge on Follicular Lymphoma (FL), the most common low-grade NHL derived from GCB cells, prompted us to develop novel mouse models to mimic the precancerous state. In FL, BCL2 translocation and CREBBP loss-of-function (LoF) mutations are characteristic of a precancerous state. These mutations can be detected years before FL diagnosis, hinting at potential immune involvement in preventing FL. Our research affirms the effectiveness of the mouse models in replicating the FL precancerous state. Mice with BCL2 overexpression (OE) alone or together with CREBBP LoF showed increased GCB cell expansion, up to 6-fold compared to control. This expansion involved reduced GCB cell death rather than increased proliferation, consistent with FL slow-growing nature. Mice harboring mutant GCB cells also exhibited a significant increase in memory B cells, up to 20-fold when compared to control. As the GC reaction progressed, the impact of CREBBP LoF emerged, profoundly altering GCB cell phenotypes, and triggering a remarkable surge in cell expansion, escalating up to 80-fold compared to mice with BCL2 OE alone or control. However, this hyperplasia was swiftly followed by a decline, indicative of immunosurveillance targeting precancerous GCB cells. Prior to the reduction of GCB cells with BCL2 OE and CREBBP LoF, we observed a notable expansion of PD1+ CD8+ T cells expressing granzyme A and perforin. These activated CD8+ T cells also expressed CXCR5, facilitating their infiltrating into the B cell follicle to specifically eliminate GCB cells with BCL2 OE and CREBBP LoF. Preemptive depletion of CD8+ T cell effectively prevented the loss of precancerous GCB cells. The examination of the GC reaction over time provided new perspectives into the immunosurveillance of precancerous GCB cells and FL development. The data supports the concept that precancerous GCB cells must overcome robust anti-tumor immunity for Lymphoma to ensue. This knowledge offers potential explanation for the infrequent and extended duration of the transition from precancerous GCB cells to full-blown FL. These models provide a foundation to explore mechanisms underlying immune evasion by precancerous GCB cells. Citation Format: Lingling Zhang, Oscar Atkins, Miu Shing Hung, Hans Christian Reinhardt, Dinis Pedro Parente Calado. Immunosurveillance of precancerous germinal center B cells [abstract]. In: Proceedings of the Fourth AACR International Meeting on Advances in Malignant Lymphoma: Maximizing the Basic-Translational Interface for Clinical Application; 2024 Jun 19-22; Philadelphia, PA. Philadelphia (PA): AACR; Blood Cancer Discov 2024;5(3_Suppl):Abstract nr PR03.

Small sized centroblasts as poor prognostic factor in follicular lymphoma - Based on artificial intelligence analysis

Histological assessment of centroblasts is an important evaluation in the diagnosis of follicular lymphoma, but there is substantial observer variation in assessment among hematopathologists.We aimed to perform quantitative morphological analysis of centroblasts in follicular lymphoma using new artificial intelligence technology in relation to the clinical prognosis. Hematoxylin and eosin slides of lesions were prepared from 36 cases of follicular lymphoma before initial chemotherapy. Cases were classified into three groups by clinical course after initial treatment. The ‘excellent prognosis’ group were without recurrence or progression of follicular lymphoma within 60 months, the ‘poor prognosis’ group were those that had relapse, exacerbation, or who died due to the follicular lymphoma within 60 months, and the ‘indeterminate prognosis’ group were those without recurrence or progression but before the passage of 60 months. We created whole slide images and image patches of hematoxylin and eosin sections for all cases. We designed an object detection model specialized for centroblasts by fine-tuning YOLOv5 and segmented all centroblasts in whole slide images. The morphological characteristics of centroblasts in relation to the clinical prognosis of follicular lymphoma were analyzed. Centroblasts in follicular lymphoma of the poor prognosis group were significantly smaller in nuclear size than those in follicular lymphoma of the excellent prognosis group in the following points: median of nuclear area (p = 0.013), long length (p = 0.042), short length (p = 0.007), nuclear area of top 10 % cells (p = 0.024) and short length of top 10 % cells (p = 0.020). Cases with a mean nuclear area of <55 μm2 had poorer event-free survival than those with a mean nuclear area of ≥55 μm2 (p < 0.0123). AI methodology is suggested to be able to surpass pathologist's observation in capturing morphological features. Small-sized centroblasts will likely become a new prognostic factor of follicular lymphoma.

Lisocabtagene maraleucel in follicular lymphoma: the phase 2 TRANSCEND FL study

An unmet need exists for patients with relapsed/refractory (R/R) follicular lymphoma (FL) and high-risk disease features, such as progression of disease within 24 months (POD24) from first-line immunochemotherapy or disease refractory to both CD20-targeting agent and alkylator (double refractory), due to no established standard of care and poor outcomes. Chimeric antigen receptor (CAR) T cell therapy is an option in R/R FL after two or more lines of prior systemic therapy, but there is no consensus on its optimal timing in the disease course of FL, and there are no data in second-line (2L) treatment of patients with high-risk features. Lisocabtagene maraleucel (liso-cel) is an autologous, CD19-directed, 4-1BB CAR T cell product. The phase 2 TRANSCEND FL study evaluated liso-cel in patients with R/R FL, including 2L patients who all had POD24 from diagnosis after treatment with anti-CD20 antibody and alkylator ≤6 months of FL diagnosis and/or met modified Groupe d’Etude des Lymphomes Folliculaires criteria. Primary/key secondary endpoints were independent review committee–assessed overall response rate (ORR)/complete response (CR) rate. At data cutoff, 130 patients had received liso-cel (median follow-up, 18.9 months). Primary/key secondary endpoints were met. In third-line or later FL (n = 101), ORR was 97% (95% confidence interval (CI): 91.6‒99.4), and CR rate was 94% (95% CI: 87.5‒97.8). In 2L FL (n = 23), ORR was 96% (95% CI: 78.1‒99.9); all responders achieved CR. Cytokine release syndrome occurred in 58% of patients (grade ≥3, 1%); neurological events occurred in 15% of patients (grade ≥3, 2%). Liso-cel demonstrated efficacy and safety in patients with R/R FL, including high-risk 2L FL. ClinicalTrials.gov identifier: NCT04245839.

Early histological transformation of follicular lymphoma to diffuse large B-cell lymphoma indicating adverse survival: A population-based analysis and validation.

The histological transformation (HT) of follicular lymphoma (FL) is a crucial biological event. The study aimed to evaluate the incidence, clinicial characteristics, prognosis and impact of HT time on survival of FL transforming to diffuse large B-cell lymphoma in population-based large-scale cohorts. A retrospective cohort study of FL with HT was performed in the Surveillance, Epidemiology, and End Results database. The Hematological Malignancy Research Network FL cohort and Aristotle study FL cohort were used to assess the external validity. Among 44,127 FL cases from the Surveillance, Epidemiology, and End Results database, 1311 cases were pathology-proven recorded to transform to diffuse large B-cell lymphoma. The cumulative rates of HT at 5, 10, and 15 years after FL diagnosis were estimated to be 1.19%, 2.93%, and 5.01%, respectively. Significantly worse overall survival and cancer-specific survival were exhibited in patients with HT than those without HT. Early HT (transformation of FL within 48 months after FL diagnosis [TOD48]) was an independent predictor for adverse overall survival of HT patients, regardless of treatment modalities before transformation. The adverse prognostic effect of TOD48 was validated in the Hematological Malignancy Research Network cohort and Aristotle study cohort. Older age (>75 years) and B symptoms within FL at diagnosis were the independent risk factors of TOD48. Furthermore, a novel prognostic model combining TOD48 with Follicular Lymphoma International Prognostic Index (TOD48-FLIPI) was constructed and validated for risk stratification. TOD48 was a risk indicator of HT, and the novel prognostic model "TOD48-FLIPI" for HT patients was proposed.

Identification and Functional Investigation of Hub Genes Associated with Follicular Lymphoma.

Follicular lymphoma (FL), the most common type of indolent lymphoma, originates from germinal center B cells within the lymphoid follicle. However, the underlying mechanisms of this disease remain unclear. This study aimed to identify the potential hub genes for FL and evaluate their functional roles in clinical applications. Microarray data and clinical characteristics of patients with FL were obtained from the Gene Expression Omnibus database. Differential expression analysis and weighted gene co-expression network analysis (WGCNA) were employed to explore hub genes for FL. Functional enrichment analysis was performed to investigate the potential roles of these hub genes in FL. Mendelian randomization (MR) analysis was performed to verify the causal effect of the top genes on FL risk. In addition, gene set enrichment analysis (GSEA) and immune cell analysis were performed to elucidate the involved mechanisms of the crucial genes in FL. A total of 1363 differentially expressed genes and 157 central genes were identified by differential expression analysis and WGCNA, respectively, resulting in 117 overlapping genes considered as hub genes for FL. Functional enrichment analysis revealed significant correlations between immune-related pathways and FL. MR analysis revealed a significant association only between zeta chain of T-cell receptor-associated protein kinase 70 (ZAP70) and FL risk, with no significance observed for the other top genes. GSEA and immune cell analysis suggested that ZAP70 may be involved in the development and progression of FL through immune-related pathways. By integrating bioinformatics and MR analyses, ZAP70 was successfully identified and validated as a promising FL biomarker. Functional investigations indicated a significant correlation between immune-related pathways and FL. These findings have important implications for the identification of targets for the diagnosis and treatment of FL and provide valuable insights into the molecular mechanisms underlying FL.

Patients with Classic Hodgkin Lymphoma and Follicular Lymphoma Compared to Single Malignancy Controls.

Classic Hodgkin lymphoma (CHL) can arise in patients with low-grade B-cell lymphoma. The features of CHL arising in follicular lymphoma (FL) and its outcome are still unclear, mainly due to the very few cases reported. This study compares 17 patients with CHL and FL to 2 control groups: 1 of 26 patients with FL and a second of 60 patients older than 40 when diagnosed with CHL. Of the FL and CHL patients, 8 had simultaneous FL and CHL, while 9 had FL first, followed by CHL 4.7 years later on average. The age at the diagnosis of FL was 61 years for patients with synchronous FL and CHL and of 60 years for FL, followed by CHL at 65 years. Patients with FL only were, on average, 59 years old at presentation, while CHL patients were 61. FL was grade 1-2 in 75% of FL and CHL patients and 67% of FL first and CHL second patients, lower proportions than in the FL control group-92%. Epstein-Barr virus (EBV) was detected in a lower fraction (29%) of the FL and CHL group than in CHL-only controls (46%). BCL2 translocations were detected in 4 of the 7 cases with FL, but in positive cases, the rearrangement was also present in the CHL component, indicating a clonal relationship between FL and CHL. Patients with FL and CHL treated for CHL had an initial outcome more similar to FL than to CHL controls.

Outcomes of the transformation of follicular lymphoma to diffuse large B-cell lymphoma in the rituximab era: A population-based study.

Histological transformation (HT) to diffuse large B-cell lymphoma (DLBCL) is a common complication of follicular lymphoma (FL) and is usually associated with a dismal outcome. However, the survival rate of these patients has improved over the last 20 years with the introduction of rituximab. This study aimed to access the outcome of transformation to DLBCL (t-DLBCL) from FL in a retrospective series that began after the widespread use of rituximab use. In addition, we also compared survival between t-DLBCL and primary DLBCL (p-DLBCL) in the same timeframe. We utilized the Surveillance, Epidemiology, and End Results (SEER) database to identify patients with primary FL and patients with p-DLBCL between 2000 and 2020. Patients who had a subsequent diagnosis of DLBCL at least 2 months after FL diagnosis were identified as t-DLBCL. Finally, we identified 50,332 FL and 95,933 p-DLBCL. With a median follow-up of 119 months, 1631 patients developed t-DLBCL. The median time from FL diagnosis to t-DLBCL was approximately 4 years. The post-transformation survival (PTS) rate at 5 years was 49.6%, with a median PTS of 56 months. Older age, advanced stage, and early transformation were associated with worse PTS. Furthermore, t-DLBCL receiving chemotherapy or combined modality as initial therapy before HT was also associated with worse PTS, while the result was inverse when taking the impact of initial management strategy at HT into account. Taking t-DLBCL and p-DLBCL as a whole, comparable survival was observed between p-DLBCL and t-DLBCL receiving radiation or watch-and-wait as initial therapy prior to HT. The outcome of t-DLBCL in the rituximab era was better than historical series before the rituximab era. Due to the good prognosis, we did not recommend autologous stem cell transplantation for t-DLBCL receiving watch-and-wait or radiation as initial therapy before HT.

457 A Phase I Trial of Tazemetostat and Venetoclax in Relapsed and Refractory non-Hodgkin Lymphoma

OBJECTIVES/GOALS: Primary Objective: To evaluate the safety of venetoclax plus tazemetostat in patients with relapsed and refractory (R/R) Follicular lymphoma (FL) or Diffuse large B-cell lymphoma (DLBCL) Secondary Objectives: 1. To evaluate the tolerability of the combination of T+V using patient reported outcomes (PROs) 2. To evaluate the efficacy of T+V METHODS/STUDY POPULATION: Study design: A phase I trial in two parts: Part 1: a single-arm, open-label sequential dose escalation (3+3) of venetoclax in combination with tazemetostat, given at its recommended phase II dose (RP2D) of 800mg BID, to determine the maximum tolerated dose (MTD) of venetoclax. Part 2: two expansion cohorts (R/R DLBCL and R/R FL) to further characterize the safety and tolerability of the combination, and to estimate the preliminary efficacy. We will perform additional exploratory studies to determine if there are biologic features that correlate with responses. Eligibility: up to 38 patients aged &gt;/=18 years old with histologically confirmed diagnosis of FL or DLBCL who have received at least 2 prior lines of therapy for lymphoma with evidence of disease progression and meet inclusion criteria RESULTS/ANTICIPATED RESULTS: Primary Endpoints: 1. Incidence and severity of adverse events as per CTCAEv5 2. Dose-limiting toxicity (DLT) of T+V, and to establish the maximum tolerated dose (MTD) of V plus fixed dose T Secondary Endpoints: 1. Incidence and Severity of toxicity and quality of life as per PRO-CTCAE and FACT-Lym 2. Overall response rate (ORR), complete response (CR) rate, partial response (PR) rate, as per Lugano criteria 3. Duration of response (DOR), progression-free survival (PFS), overall survival (OS)Exploratory Endpoints: 1. Characterization of tumor cells pre-treatment (including EZH2 mutations and BCL2 translocations) 2. Phenotypic analysis (including BCL2 expression) and quantification of the tumor microenvironment in pre-treatment samples (using image mass cytometry)Explorato DISCUSSION/SIGNIFICANCE: There is a need for novel therapeutic approaches to improve the prognosis for patients with R/R NHL. Preclinical data suggests synergism between the pair.5 Importantly, this represents a chemotherapy-free, oral regimen. If well tolerated, this could present an alternative therapeutic option for patients ineligible for more intensive therapies.

Follicular lymphoma with a predominantly diffuse growth pattern with 1p36 deletion: a clinicopathologic analysis of eight cases

Objective: To investigate the clinical and pathologic features and diagnosis of follicular lymphoma (FL) with a predominantly diffuse growth pattern (DFL) with 1p36 deletion. Methods: Eight cases of DFL with 1p36 deletion diagnosed at Department of Pathology, Beijing Friendship Hospital, Capital Medical University (n=5) and the Affiliated Cancer Hospital of Zhengzhou University, Henan Cancer Hospital (n=3) from January 2017 to January 2023 were included. Their clinicopathologic features and follow-up data were analyzed. Immunohistochemistry and fluorescence in situ hybridization (FISH) were performed. Results: There were five males and three females, with a median age of 67 years, and inguinal lymphadenopathy was found as the main symptom. Histologically, similar morphologic features were sheared among all cases, with effaced nodal structure and characterized by proliferation of centrocytes in a diffuse pattern, with or without follicular components. The germinal center-related markers such as CD10 and/or bcl-6 were expressed in the tumor cells, and 1p36 deletion but not bcl-2 translocation was appreciable in these cases. Conclusions: DFL with 1p36 deletion is a rare subtype of FL, with some overlaps with other types of FL or indolent B-cell lymphomas in their pathologic features. An accurate diagnosis requires comprehensive considerations based on their clinical, pathologic, immunohistochemical, and molecular features.

Performance of the cobas EZH2 mutation test on clinical samples from non-Hodgkin lymphoma patients

Objective To present the technical verification and clinical validation of the companion diagnostic assay, cobas® EZH2 Mutation Test (cobas EZH2 Test), targeting gain-of-function EZH2 mutations in follicular lymphoma (FL) and diffuse large B-cell lymphoma (DLBCL). The focus is on patient clinical samples proving that the test met the performance criteria required for FDA approval of a companion diagnostic test. Design Epizyme, Inc., Eisai Co., Ltd., and Roche Molecular Systems, Inc., collaborated to develop the cobas EZH2 Test on an RT-PCR platform. The assay design needed to detect the gain-of-function EZH2 mutations found in FL and DLBCL indications. Thus, the test was optimized for investigational purposes in a clinical trial setting. Part of its technical verification included testing of patient tumor samples with a documented diagnosis of FL and DLBCL procured from commercial vendors, and the clinical validation used patient samples from the Epizyme clinical study. Both the technical performance verification method correlation study (104 clinical commercially acquired samples) and the clinical validation accuracy study (341 patient samples from the therapeutic study) used next-generation sequencing as a reference method to establish true vs. false results by cobas EZH2 Test. The reproducibility study used a 15-member panel of DNA samples with varying EZH2 mutation status from procured clinical FL and DLBCL patient samples under multiple variables. Results Single and rare, infrequent double EZH2 mutations were detected in FL and DLBCL samples. Agreements between results from cobas EZH2 and sequencing were &gt;98% from commercial clinical samples and from the therapeutic study clinical samples. The reproducibility study obtained 178 to 180 valid results for each panel member, with an overall invalid rate of 0.37%. The agreement for each per panel member was 100%. Conclusion cobas EZH2 Test data demonstrated that the test is reliable and will perform well in a commercial customer environment.

Digital and manual interfollicular Ki-67 are associated with a progression-free survival in patients with low-grade follicular lymphoma.

Novel histopathologic prognostic factors are needed to identify patients with follicular lymphoma (FL) at risk of inferior outcomes. Our primary objective was to evaluate the Ki-67 proliferative index in follicular and interfollicular areas in tissue biopsy specimens from patients with newly diagnosed FL and correlate with clinical outcomes. Our secondary objective was to correlate PD-L1 and LAG-3 with clinical outcomes. Seventy cases of low-grade FL from the University of Minnesota were evaluated with Ki-67 immunohistochemical stain. Ki-67 expression as a continuous variable was interpreted digitally and manually in follicular and interfollicular areas. Progression-free survival (PFS) and overall survival (OS) were analyzed by Cox regression, and hazard ratios (HRs) per 10-point increase in Ki-67 were calculated. Progression-free survival at 4 years was 28% (95% CI, 19%-41%). Interfollicular, but not follicular, Ki-67 was associated with PFS by manual (HR, 1.33; P = .01) and digital (HR, 1.38; P = .02) analysis. Digital and manual Ki-67 were only moderately correlated but demonstrated similar effects on PFS. At 4 years, OS was 90% with no association with follicular or interfollicular Ki-67 proliferation. Higher interfollicular Ki-67 by either digital or manual analysis is associated with a poorer PFS in patients with low-grade FL. These results suggest further validation of this marker is warranted to improve pathologic risk stratification at FL diagnosis. PD-L1 and LAG-3 were not associated with PFS or OS.

Concurrent metastatic melanoma and follicular lymphoma diagnosis on liver fine needle aspiration and biopsy

Abstract Introduction/Objective The liver is commonly involved in metastatic neoplasms, such as colorectal, breast, esophageal, stomach, pancreatic, lung, and kidney. Fine needle aspiration (FNA) and core needle biopsy (CNB) are frequently used to establish an accurate diagnosis of liver masses. Here we report the coexistence of metastatic malignant melanoma (MM) and follicular lymphoma (FL) involving the liver. To our knowledge, This is the first reported case, and we hope to add to the literature. Methods/Case Report The patient is a 75 -year-old woman diagnosed with stage I skin melanoma in 2004, and systemic low-grade FL in 2009. She presented with fatigue, weight loss, and difficulty swallowing. CT scan showed new pulmonary, hepatic, and splenic nodules with stable abdominal lymphadenopathy. Smears from the liver nodule FNA showed numerous single tumor cells with moderate cytoplasm and eccentrically located hyperchromatic nuclei. CNB showed fragments of liver parenchyma infiltrated by metastatic melanoma and a focal portal area with expansile lymphoid aggregates of small lymphocytes. The lymphoid cells were positive for CD10, CD20, PAX5, and BCL2 and negative for CD3, CD5, BCL6 and BCL1, with a low Ki-67 proliferative index (&amp;lt;5%). Although not characteristic of an FL, this immunophenotype was most consistent with FL given her clinical history. The metastatic MM was positive for SOX10 and Melan-A, while negative for CD45 and CK AE1/AE3. Despite neoadjuvant therapy, the patient died just two months after diagnosis. Results (if a Case Study enter NA) NA Conclusion A tremendous variety of neoplasms can occur in the liver. Different morphologies under a microscope should broaden the list of differential diagnoses. Familiarizing with morphological features and using ancillary studies are essential for accurate diagnosis and proper patient management. FNA and CNB combined with ancillary studies can successfully establish the diagnosis of malignancies involving the liver.

Real-World Response Rates across Lines of Therapy Among Patients with Relapsed/Refractory Follicular Lymphoma

Background: Follicular lymphoma (FL) is the most common indolent subtype of non-Hodgkin lymphoma. Despite the generally indolent nature of the condition, there are subgroups of FL patients who may not have an indolent experience, with their disease not responding to multiple lines of therapy. Thus, optimization of novel therapy could improve patient outcomes. This analysis examined treatment patterns, overall response rates (ORR), and complete response (CR) rates by line of therapy (LOT) in relapsed/refractory (R/R) FL in third-line or later (3L+) therapy. Methods: This retrospective observational study was conducted using the COTA database, comprising electronic health records (EHR) from academic (50%) and community (50%) practices in the US. Adults with a confirmed diagnosis of FL, with 3L+ therapy initiation in 2010 or later, at least 3 months of follow-up, and any response assessment after 3L initiation were included. LOTs eligible for inclusion met the following conditions: treatment with an anti-CD20, alkylating agent, or lenalidomide, and no investigational drug in the selected LOT. In addition, patients with only 3L had that line selected; patients with more than 1 eligible LOT had only 1 LOT randomly selected for the analysis. Outcomes were assessed by FL International Prognostic Index (FLIPI), double refractory (DR) status, and type of therapy. DR status was defined as being refractory (disease progression or initiation of a new LOT in &amp;lt;6 months) to an anti-CD20 monoclonal antibody therapy and an alkylating agent. Chemoimmunotherapy (CIT) regimens included obinutuzumab/rituximab + bendamustine (OB/BR), rituximab/obinutuzumab+cyclophosphamide, doxorubicin, vincristine, and prednisolone (R/O+CHOP), R/O+CVP, R/O+other alkylating agent, and R/O+fludarabine and cyclophosphamide (FC). Novel therapies included lenalidomide + rituximab (R 2), phosphatidylinositol-3-kinase (PI3K) inhibitors, and chimeric antigen receptor T-cell therapy (CAR T). The proportion of patients with CR (as retrieved from clinician documentation in EHR) as the physician-reported response within each LOT was calculated. ORR was calculated as the proportion of patients with a CR or PR. Response rates were reported by LOT (3L, 4L, 5L+) and stratified by patient age (&amp;lt;65 vs ≥65 years), FLIPI score (low/intermediate vs high), and DR (not DR vs DR). Results: Overall, 240 patients with R/R 3L+ FL were included: 3L (n=140), 4L (n=55), and 5L+ (n=45). At 3L initiation, median age was 66 years and most patients were male (58.8%), White (89.6%), and had FL grade 1/2 (72.5%); 47.9% of patients were DR, 22.9% had novel therapy use, and 51.3% had CIT use. A total of 152 patients had FLIPI scores available, 38.2% of whom had high-risk scores at 3L initiation. Among all R/R 3L+ FL patients, ORR was 67.9%, with CR in 30.4% ( Figure 1). Response rates decreased across LOTs for both ORR (3L: 72.9%; 4L: 65.5%; 5L+: 55.6%) and CR (3L: 35.0%; 4L: 30.9%; 5L+: 15.6%) ( Figure 2). ORR was higher among all R/R 3L+ FL patients &amp;lt;65 years vs ≥65 years (75.5% vs 62.3%), as was CR rate (36.3% vs 26.1%). Among the subset of R/R 3L+ FL patients with a FLIPI score, those with low/intermediate risk vs high risk had a greater ORR (78.7% vs 58.6%) and CR rate (36.2% vs 20.7%). ORR was also higher for R/R 3L+ patients without DR status vs with DR status (73.0% vs 63.2%), as was CR rate (37.4% vs 24.0%). Patients receiving novel therapy 3L+ had an ORR of 70.9% and a CR rate of 27.3%. Among R/R 3L+ FL patients, more LOTs of CIT were associated with decreased response rates; patients with CIT in 1 LOT vs CIT in &amp;gt;2 LOTs had greater ORR (76.4% vs 69.2%) and CR rate (37.4% vs 26.9%). Conclusions: This analysis provides granular details on patients with R/R FL with poor prognosis. Patients with FL who progress to later LOTs have worsening response rates. This analysis included more patients with later LOTs than previously published reports, providing additional insight into response rates as treatment progresses. Lower response rates were observed among patients ≥65 years, those with a high-risk FLIPI score, and those with DR status. The high utilization of CIT in later LOTs, despite suboptimal response rates, especially among subgroups of patients with FL who may not have indolent experience of the disease, underlines the need for efficacious alternative therapies in patients with R/R 3L+ FL.

Increased Frequency of Low-Grade Follicular Lymphoma with a High Proliferative Index: A First Step Towards Histological Transformation? a Retrospective Analysis of 25 Follicular Lymphoma Cases

Background: The most common form of indolent non-Hodgkin's lymphoma (NHL) is follicular lymphoma (FL). Although the overall survival of patients is currently over 20 years, 2-3% per year will suffer from histologic transformation. Patients with low-grade (WHO 1-2) FL with high proliferative index (PI), defined as Ki-67 expression ≥30%, have a shorter time to first treatment and worse disease-specific survival. Low-grade high-proliferative index (LG-HPI) is reported to account for 20% of low-grade FL cases. A specific clinical approach for LG-HPI is still controversial. Here, we report an increased frequency of LG-HPI cases in our institution and their associated clinical characteristics. Methods: We retrospectively analyzed a cohort of adult patients with a confirmed diagnosis of FL. Included patients had a tissue biopsy with defined Ki-67 by immunohistochemistry (IHC) and were categorized according to the WHO classification. A high proliferative index (PI) was defined as Ki-67 ≥30%. To compare their characteristics, patients were divided into three different categories: those with low grade and high proliferative index (LG-HPI), those with low grade and low proliferative index (LG-LPI), those with high grade (HG) including 2 cases with histologic transformation. All clinical and laboratory data were retrieved from the electronic clinical database. Frequencies of categorical variables were described as percentages, while continuous variables were described as medians. Comparisons were made using ANOVA. Results: A total of 25 patients were evaluated. The median age at diagnosis was 66 years and 40% were female (10). 17 patients had low-grade FL (68%), six had WHO 3a high-grade FL (24%), and two had transformed high-grade FL (8%). 14 patients (56%) were diagnosed at a localized stage (I - II) and eleven at an advanced stage (44%). After diagnosis, five patients were initially observed (20%), three received radiotherapy as a single treatment (12%), and 17 received chemoimmunotherapy (68%). For actively treated patients, the median time from diagnosis to treatment was 18 days (range 2 - 392 days). Overall, the median Ki-67 expression was 40% (range 3 - 90). Of the low grade FL patients, nine were LG-LPI (53%) and eight were LG-HPI (47%). Patients with LG-LPI had lower LDH levels and baseline SUVmax, which reached significance when compared to HG ( Figures 1 &amp; 2). All patients initially observed at diagnosis were LG-LPI. We found no differences in hemoglobin, stage, albumin, beta-2 microglobulin, IgG and response to treatment between these groups. Data on progression or overall survival are yet immature. Discussion: Our data suggest that patients with LG-HPI may represent a higher proportion of FL cases than previously reported. Consistent with previous reports, LG-HPI is clinically more aggressive than LG-LPI and may represent an intermediate step toward transformation. Further improvements in quantitative Ki-67 standardization are needed to define its prognostic and clinical role.

A Predictive Model Based on Machine Learning for Early Progression/Relapse of Follicular Lymphoma

Introduction:Management of follicular lymphoma (FL) improved dramatically in the last decade, and progression/relapse of disease within 24 months (POD24) is now established as a predictor for poor survival. Risk prediction of early POD (E-POD) prior to the start of therapy may enhance clinical management and research strategies. We aimed to establish a comprehensive model based on machine learning (ML) that could predict the E-POD of FL patients for earlier identify such patients earlier. Methods: In this study, patients with a diagnosis of FL at the Shandong Provincial Hospital between January 1, 2010, to May 1, 2023, were identified retrospectively. All patients met the following criteria: pathologically confirmed with grades 1-3A FL and no previous treatment for FL. Model building was performed on a 70% split sample based on ML algorithms, and with 30% held for internal testing. Model performance was evaluated using the ROC curve, accuracy, precision, and f1-score. Furthermore, we compared the features of FL patients with early (&amp;lt;2 years) and late POD (relapsing after 5 years of starting treatment, L-POD). This study was in accordance with the Declaration of Helsinki and it was approved by the Medical Ethical Committee of the Shandong Provincial Hospital. All patients were obtained for the collection of informed consent at their first visit. Results: Of the included 224 patients, 45 (20.1%) had at least one POD. E-POD occurred in of the 29 (64.4%) evaluable patients and 6 (13.3%) had late POD (relapsing after 5 years of starting treatment, L-POD), In our center, the median age at the time of the FL diagnosis was 49 years (range 19-82), and the median length of follow-up was 28 months (range 3-120). Most patients were diagnosed with advanced disease (80.8%) and had grade 1-2 disease (75.9%). 75 cases (33.9%) had bone marrow participation and 63 cases (28.1%) with Ki-67≥30%. To establish a scoring system for predicting E-POD, we selected 34 variables for served as the input candidate features, including sociodemographic, clinical, and immunohistochemistry data, and used lymphoma E-POD (yes or no) as the output variable. In 14 models based on ML algorithms, the best models were RF Classifier (AUC: 0.83, Accuracy: 89.5%). To improve the performance, it was optimized after the complete construction of the model. Finally, the RF Classifier demonstrated AUC and accuracy as follows: 0.96, and 92.3% and we calculated the recall, precision, and F1 scores based on the confusion matrix as follows: 84.1%, 97.4%, and 90.3%, respectively. We evaluated the performance of prediction models built with data in a validation cohort and found the performance of the model was similar in both cohorts. Based on this RF Classifier, we selected relative variables important out of the multiple clinical and laboratory blood markers to predict E-POD ( Fig. 1A). Meanwhile, we analyzed the Pearson correlation coefficients (r) between 20 statistically meaningful biomarkers to reduce the complexity of the model ( Fig. 1B). To further screen for prognostic biomarkers, the top ten risk factors from the three best-performing models were integrated. The five biomarkers were completely involved in these three modules, including adenosine deaminase (ADA), β2-macroglobulin (β2-MG), C-reactive protein (CRP), aspartate transaminase (AST), and D-dimer. Additionally, we also found a significant difference in OS between the clusters among FL patients (p&amp;lt;0.05). Among 224 patients with FL, 45 (20.1%) patients experienced recurrence and progression. Besides 23 (60.5%) cases with E-POD, there are 6 (15.8%) patients who had L-POD. In comparison with those who experienced E-POD, L-POD patients showed a trend toward a better outcome, and a more favorable risk profile at presentation: lower pathological grade (1-2), anemia, and no mutation of the CARD11. Conclusion: We established a prognostic model to identify a subgroup of patients at high risk of E-POD based on AI analysis. This model utilizes objective variables easily and reliably measured at diagnosis which makes it easier for clinicians to predict the E-POD risk of FL and dynamically monitor changes during treatment. Further validation will hopefully facilitate the incorporation of these simple biomarkers into clinical decision-making tools to prevent adverse outcomes and promote personalized treatment options.

Pirtobrutinib, a Highly Selective, Non-Covalent (Reversible) BTK Inhibitor in Relapsed/Refractory Follicular Lymphoma: Results from the Phase 1/2 BRUIN Study

Background: Follicular lymphoma (FL) is a chronic and incurable disease requiring multiple lines of therapy for patients (pts) with relapsed/refractory (R/R) disease. Covalent Bruton tyrosine kinase inhibitors (cBTKi) have transformed the management of select B-cell malignancies, in particular chronic lymphocytic leukemia (CLL) and mantle cell lymphoma (MCL). However, despite the transformative impact in CLL and MCL, the efficacy of single-agent cBTKi has been limited in pts with R/R FL, with an overall response rate (ORR) of 20.9% to 37.5% (Gopal et al, J Clin Oncol, 2018; Bartlett et al, Blood, 2018). Pirtobrutinib, a highly selective, non-covalent (reversible) BTKi, inhibits both wildtype and C481-mutant BTK with equal low nM potency and has a favorable oral pharmacology that enables continuous BTK inhibition throughout the once-daily dosing interval. Pirtobrutinib has demonstrated promising efficacy and tolerability in pts with poor-prognosis B-cell malignancies following prior therapy, including cBTKi. Here, we report the safety and efficacy of pirtobrutinib in a cohort of pts with R/R FL from the BRUIN study (NCT03740529). Methods: Pts with previously treated B-cell malignancies were eligible for treatment with pirtobrutinib monotherapy in either the dose escalation or expansion portion of the multicenter phase 1/2 BRUIN study. FL diagnosis required pathologic review of an adequate biopsy. Key endpoints included investigator-assessed ORR per Lugano 2014 criteria, duration of response (DoR), progression-free survival (PFS), overall survival (OS), and safety. A data cutoff date of 05 May 2023 was utilized. Results: Among the 48 pts with FL, 45 (94%) pts received the recommended phase 2 dose of pirtobrutinib (200 mg once daily) as their starting dose. Pts had a median age of 64.5 years (range, 37.0-85.0), were mostly male (60%, n=29), and had a median of 3 (range, 1-12) prior lines of therapy. Most pts (81%, n=39) had Ann Arbor stage III/IV disease. The Follicular Lymphoma International Prognostic Index (FLIPI) risk was low (0-1) in 9 (19%) pts, intermediate (2) in 13 (27%) pts, high (3-5) in 23 (48%) pts, and missing in 3 (6%) pts. Overall, 43 (90%) pts had received chemotherapy plus an anti-CD20 antibody, 17 (35%) pts had received a PI3K inhibitor, 14 (29%) pts had received lenalidomide, 6 (13%) pts had received an autologous stem cell transplant, and 4 (8%) pts had received CAR T-cell therapy. Of the 4 (8%) pts who had received a prior cBTKi, 3 discontinued due to disease progression and 1 discontinued for intolerance. The ORR was 50.0% (95% confidence interval [CI], 35.2-64.8), including 7 (14.6%) complete responses and 17 (35.4%) partial responses (Figure). An additional 12 (25.0%) pts had stable disease. Among 4 pts who had received prior cBTKi, 3 achieved partial response and 1 had stable disease. With a median follow-up of 18.4 months (interquartile range, 10.1-21.0) among 24 responding pts, median DoR was 5.5 months (95% CI, 3.7-not estimable [NE]), and the 18-month estimated DoR rate was 41.0% (95% CI, 20.1-60.9). Median PFS was 5.8 months (95% CI, 3.8-8.1), and the 18-month estimated PFS rate was 32.3% (95% CI, 19.1-46.2). Median OS was NE, and the 18-month estimated OS rate was 78.3% (95% CI, 62.1-88.1). The efficacy outcomes by FLIPI risk category are presented in the Table. The median time on treatment was 7.6 months (range, 0.6-42.2), with 14 (29.2%) pts still receiving pirtobrutinib. The most frequent treatment-emergent adverse events (TEAEs), regardless of attribution, were diarrhea (29.2%, n=14), fatigue (25.0%, n=12), and nausea (22.9%, n=11). TEAEs of hemorrhage/hematoma (6.3%, n=3), hypertension (4.2%, n=2), and atrial fibrillation/flutter (2.1%, n=1) were infrequent. The most frequent grade ≥3 TEAEs were infection (18.8%, n=9) and neutropenia/neutrophil count decreased (14.6%, n=7). Only 1 (2.1%) pt had a treatment-related adverse event (rash) that led to pirtobrutinib discontinuation. Conclusions: In this cohort of heavily pre-treated pts with R/R FL, pirtobrutinib showed potential efficacy and was well tolerated, including in pts with high risk FLIPI.

Association of Vaccination and Current Immunotherapy with COVID-19 Outcome in Patients with Follicular Lymphoma: A Retrospective Study

Introduction Immunotherapy (IO) based on anti-CD20 monoclonal antibodies significantly improves the prognosis of patients with follicular lymphoma (FL) in terms of disease progression, progression-free survival (PFS) and serious adverse events. Vaccination is protective in the general population, however, FL patients infected with COVID-19 have exacerbated damage to their immune system, and the effects of IO and vaccination on COVID-19 outcomes remain unknown. The aim of this study was to estimate the association between IO therapy based on anti-CD20 monoclonal antibody and COVID-19 severity by analyzing population-based data of FL patients. And to determine the true utility of vaccination in this immunocompromised population. Patients and methods We retrospectively assessed the clinical characteristics and follow-up data of patients with newly diagnosed FL from December 1, 2012 to April 1, 2023 at Shandong Provincial Hospital. Patients were divided into 2 groups: those who received IO, defined as anti-CD20 immunotherapy, within 12 months prior to COVID-19 diagnosis (IO group); those who received non-IO antitumor regimens with no systemic therapy (non-IO group), defined as cytotoxic chemotherapy, targeted therapies, endocrine therapies or those who did not receive any systemic therapy. Inclusion of data on anti-CD20 immunotherapy drugs Rituximab and Obinutuzumab applied in our center, stage of treatment, etc. COVID-19 outcomes were graded primarily on the basis of hospitalization, oxygenation, and need for mechanical ventilation, and patients' overall survival (OS) as well as PFS were studied. Multivariate logistic regression analyses were performed to assess associations between variables and COVID-19 outcomes, and unadjusted odds ratios (OR) and 95% confidence intervals (95%CI) were reported. Results Out of 160 patients included in the study ,77 (48.0%) were female, the median age was 53 (28-85 years) years, and the median follow-up was 54 (12-168 months) months. 131 (81.9%) patients had Ann Arbor stage III-IV on initial admission at our center, and 84 (52.5%) patients received the COVID-19 vaccine. Regarding COVID-19 infection, 137 (85.6%) were positive for COVID-19. 60 patients (37.5%) received IO, whereas 100 patients (62.5%) did not. Significant differences (P &amp;lt; 0.05) were found between the IO and non-IO groups in terms of COVID-19 outcome, time between COVID-19 diagnosis and FL diagnosis, and time to conversion after COVID-19 positivity (Figure 1A). There were also significant differences between the two groups in survival time and recurrent lung infection after COVID-19 cure (Figure 1B). No significant effect of vaccination on outcome of COVID-19 was found regardless of IO treatment. In the IO group, 42 (70.0%) patients received Rituximab and 18 (30%) patients received Obinutuzumab. No significant differences in COVID-19 infection rate, COVID-19 clinical outcome, time to COVID-19 conversion, and survival time were found between the two drugs. Of the patients who received IO therapy, 19 (31.7%) were in the induction phase and 41 (68.3%) were in the maintenance phase. Patients receiving maintenance therapy had a greater likelihood of longer survival（P&amp;lt;0.0001）and less severe COVID-19 outcomes（P=0.003）. Of the 60 patients treated with IO, 36 (60.0%) had an unchanged chemotherapy course and 24 (40.0%) had a delayed or interrupted chemotherapy course. No significant associations were found between IO therapeutic agents, vaccinations, or other variables with chemotherapy progression. Conclusions Among FL patients included in the analysis, IO was associated with worse COVID-19 outcomes, but no significant correlation was found between vaccination and COVID-19 infection rates and severity at this time. These findings provide insights into the immunocompromised population of FL-combined COVID-19 patients that can be used in the clinical setting to estimate COVID-19 outcomes based on factors such as chemotherapy stage and vaccination.

TRANSCEND FL: Phase 2 Study Primary Analysis of Lisocabtagene Maraleucel as Second-Line Therapy in Patients with High-Risk Relapsed or Refractory Follicular Lymphoma

Background: Results with CD19-directed CAR T cell therapy in patients (pts) with second-line (2L) R/R follicular lymphoma (FL) and high-risk features, such as progression of disease within 24 months (POD24) from diagnosis or double refractory to anti-CD20 antibody plus alkylator, have not been previously reported. TRANSCEND FL (NCT04245839), a global, phase 2, open-label, single-arm, multicohort, pivotal study, assessed efficacy and safety of the anti-CD19 CAR T cell therapy lisocabtagene maraleucel (liso-cel) in pts with second line or later (2L+) R/R indolent NHL. Some data from the primary analysis were previously reported, including safety in 2L+ R/R FL, and focused on efficacy in third line or later R/R FL (Morschhauser F, et al. Hematol Oncol 2023;41[S2]:877‒880). Here, we report primary analysis results in the cohort of pts with 2L high-risk R/R FL. Methods: Eligible pts in the 2L R/R FL cohort had biopsy-confirmed FL before enrollment and must have had POD24 with treatment ≤ 6 months from original FL diagnosis and/or must have had high tumor burden as defined by modified Groupe d'Etude des Lymphomes Folliculaires (mGELF) criteria. All pts received 1 prior combination systemic therapy with an anti-CD20 antibody and alkylator. Eligible pts received liso-cel (100 × 10 6 CAR + T cells) after lymphodepleting chemotherapy (LDC). Bridging therapy was allowed with reconfirmation of PET-positive disease before LDC. The primary endpoint was ORR per independent review committee (IRC) by PET/CT using Lugano 2014 criteria. Secondary endpoints included CR rate, duration of response (DOR), PFS, OS, safety, and cellular kinetics. Pharmacodynamic endpoints were exploratory. Results: At data cutoff (January 27, 2023), 23 of 25 leukapheresed pts received liso-cel and were evaluable for safety and efficacy per IRC; 1 received nonconforming product and 1 reached CR after bridging therapy and no longer met eligibility criteria. Median (range) age was 53 y (34-69), 74% had stage III/IV disease, and 35% were high-risk per FL International Prognostic Index (FLIPI). Sixty-five percent of pts had POD24 from initiation of first-line combination chemoimmunotherapy (52% had POD24 from diagnosis), 70% met mGELF criteria (mGELF only, 48%; mGELF and POD24 from diagnosis, 22%), and 48% were double refractory to anti-CD20 antibody plus alkylator. Median (range) on-study follow-up was 18.1 months (1.0-26.8). In efficacy-evaluable pts, the ORR and CR rate were both 95.7% (95% CI, 78.1-99.9; 1-sided P &amp;lt; 0.0001; Table). With a median follow-up of 16.8 months and 17.8 months, respectively, median DOR and PFS were not reached; 12-month DOR and PFS were 89.8% and 91.3%, respectively. The most common grade (gr) ≥ 3 treatment-emergent AEs (TEAE) were cytopenias; neutropenia was most frequent (52%). Cytokine release syndrome (CRS) occurred in 12 (52%) pts (no gr ≥ 3). Median (range) time to onset and resolution of CRS was 6 days (2-9) and 3 days (2-7), respectively. Neurological events (NE) occurred in 4 (17%) pts, with 1 (4%) gr 3 and no gr 4-5 (Table). Median (range) time to onset and resolution of NEs was 8.5 days (6-11) and 2.5 days (1-4), respectively. Three (13%) pts received tocilizumab/steroids for CRS/NEs. Prolonged cytopenia (gr ≥ 3 laboratory values at Day 29) occurred in 3 (13%) pts; all recovered to gr ≤ 2 by Day 90. No gr ≥ 3 infections were reported. One TEAE death occurred in the context of IRC-assessed disease progression due to gr 5 macrophage activation syndrome (MAS). Liso-cel showed rapid expansion with median (range) time to maximum transgene levels of 10 days (7-11). Persistence of liso-cel transgene was detected up to Month 12 in 5 of 18 (28%) pts. B-cell aplasia (&amp;lt; 3% CD19 + B cells in peripheral blood lymphocytes) after liso-cel infusion was rapid and maintained in ≥ 95% of pts through Month 2. Conclusions: This is the first report of outcomes in 2L high-risk R/R FL with CD19-directed CAR T cell therapy. In this population, liso-cel achieved very high CR rates (22 of 23 pts); deep and durable remissions, with follow-up ongoing; and a favorable safety profile with low rates of severe (gr ≥ 3) CRS, NEs, and prolonged cytopenia, and no severe infections. These data support liso-cel as a potential new treatment option in pts with 2L R/R FL at high-risk for treatment failure.