Cases Of Follicular Lymphoma Research Articles

Constrained FL: A Genetically Distinct Subgroup of Follicular Lymphoma with Low Rates of Somatic Hypermutation and a Reduced Propensity for Histologic Transformation

Constrained FL: A Genetically Distinct Subgroup of Follicular Lymphoma with Low Rates of Somatic Hypermutation and a Reduced Propensity for Histologic Transformation

Molecular and Genetic Characterization of Tumor Samples from Patients with Relapsed or Refractory Follicular Lymphoma Identifies Factors Influencing Response to Tazemetostat

Molecular and Genetic Characterization of Tumor Samples from Patients with Relapsed or Refractory Follicular Lymphoma Identifies Factors Influencing Response to Tazemetostat

Transformation of Follicular Lymphoma into Primary Mediastinal B-Cell Lymphoma-like Large B-Cell Lymphoma

Objectives: We identified a case of follicular lymphoma (FL) that transformed into a morphologic diffuse large B-cell lymphoma (DLBCL), which by gene expression profiling showed a primary mediastinal (PMBL)-like gene expression profile (GEP) (Lymph3Cx; Blood 2018;132:2401-5). A search identified 4 additional transformed FL (tFL) cases with a PMBL-like GEP, which we further studied to determine how similar these tFLs were to classic cases of PMBL.Methods: The morphology and previously reported immunophenotype were reviewed, and CD30, CD23, MAL, CD273/PDL2, and CD200 immunohistochemical stains (IHC) were performed. Whole exome sequencing (WES) and copy number analysis (CNA) to evaluate genes typically altered in FL and PMBL were performed.Results: None of the tFLs arose in the mediastinum or had a previous history of mediastinal disease. All cases showed typical centroblastic DLBCL cytology, with fine sclerosis typical of PMBL. 3/3 were GCB by the Hans IHC algorithm, 1/3 were MYC+, 3/3 BCL2+, 1/5 CD30+, 3/5 CD23+, 4/5 MAL+, 0/5 CD273/PDL2+, 1/5 CD200+, and 0/2 EBER+. Rearrangements of MYC, BCL2, or BCL6 were identified by FISH in 0/3, 1/3, and 2/3 cases, respectively. WES demonstrated sequence variants in genes associated with both FL (CREBBP [60%], KMT2D [40%], and TNFRSF14 [40%]) and PMBL (JAK-STAT pathway genes [80%], B2M [20%], and CD58 [20%]). 2 of the mutations identified in the tFLs have previously been shown to result in JAK-STAT activation (STAT6 p.E372K [PNAS 2016;113:13015-20] and SOCS1 p.F101L [Oncogene 2002;21:4351-62] identified in 1/5 cases each). CNA showed gains/amplification of REL in 3/5 cases, gains/amplification of STAT6 in 2/5, gains of large sections of chromosome 16, including IL4R, in 2/5, and both deletions and gains of 11q in 1/5. See Figure demonstrating the 5 cases on the Y-axis and the chromosomes on the X-axis.Conclusions: The tFLs in this small series seem to represent PMBL-like DLBCLs, rather than classic PMBLs, and have a blended pattern of immunophenotypic and genomic features between FL/DLBCL and PMBL. Although the cases express some PMBL-associated markers (CD23 and MAL), there is less frequent staining for others (CD30, CD273/PDL2, and CD200). The cases harbor both FL-associated and PMBL-associated sequence variants, including 40% with mutations known to activate the JAK-STAT pathway. This frequency of mutations in JAK-STAT pathway genes is higher than that seen in typical FL/DLBCL, but perhaps lower than in classic PMBL (Blood 2019;134:802-13). PMBL also frequently has gains/amplifications of 9p24.1, which was not seen in our cohort. However, gains/amplification of REL/2p, which is seen in approximately 50% of PMBL, was identified in 60% of the tFLs. The 11q aberration identified in 1 case would be unusual for PMBL, and is instead more commonly associated with a subset of aggressive lymphomas with Burkitt-like features (Haematologica 2019;104:1822-9). Recently, lymphomas with similar blended features between DLBCL and PMBL, which were not arising in the setting of tFL, have been reported (Duns G, et al. Blood 2021). Our study extends the types of biological transformations, in addition to more classic DLBCL, that can be seen in FL. These tFLs with blended PMBL-DLBCL biology may have implications for therapeutic decision making including targeted therapies used in PMBL. [Display omitted] DisclosuresRimsza: NanoString Technologies: Other: Fee-for-service contract. Steidl: Curis Inc.: Consultancy; Trillium Therapeutics: Research Funding; Bayer: Consultancy; Epizyme: Research Funding; Seattle Genetics: Consultancy; AbbVie: Consultancy; Bristol-Myers Squibb: Research Funding.

Immunohistochemical Characterization of H3K4Me3 in Reactive Lymph Nodes and Follicular Lymphoma

Abstract Introduction/Objective Genes involved in histone methylation are frequently mutated in non-Hodgkin’s lymphomas. For instance, frequent mutations in genes encoding histone methytransferases MML2 and EZH2 are present in diffuse large B cell lymphoma (DLBCL) and follicular lymphoma (FL). The aim of this study was to characterize the immunohistochemical expression of H3K4Me3 in benign/reactive lymph nodes (LNs) with comparison to follicular lymphoma (FL). Methods/Case Report Immunohistochemical staining with an anti-H3K4Me3 antibody was performed on FFPE whole slide section from patients with benign/reactive LNs (n=21), low grade (grade 1-2) FL (n=21). H3K4Me3 reactivity was scored for staining intensity and percentage of lymphocytes showing reactivity. Results (if a Case Study enter NA) The majority of the reactive LN sections (15 out of 21 cases) showed a distinct distribution of H3K4Me3 staining, with the majority of cells in the mantle zone and the interfollicular zones showing moderate-strong staining, whereas reactive germinal centers (GCs) showed significantly decreased or close to negative staining. Neoplastic follicles in all the FL cases contained positive cells with significantly stronger staining compared to that in the germinal centers in benign lymph nodes. The interfollicular zones, while diminished in FL due to expanded neoplastic follicles, showed retained H3K4Me3 staining. The difference in staining intensity between follicles and mantle/interfollicular zones became indistinct in FL. Conclusion H3K4Me3 expression in benign/reactive LNs is characterized by positive expression in lymphocytes in interfollicular and mantle zones and significantly decreased in GCs. However, the expression pattern is different in FL, which showed significantly increased expression in the follicles compared to that in reactive GCs. In FL, the expression in GCs is similar to that in the interfollicular and mantle zone lymphocytes. It is reported that about 90% of FL have MLL2 mutation and MLL2 is the enzyme responsible for the methylation of H3K4. So far, it is unclear whether the mutation of MLL2 in FL affects the overall methylation activity of the enzyme. In our study, there is increased methylation of H3K4 in the follicles of FL, which raises the possibility that MLL2 mutation somehow increases H3K4 methylation.

Two Cases of The Follicular Lymphoma of The Breast: An Exceedingly Rare Presentation

Abstract Introduction/Objective The primary Non-Hodgkin lymphoma of the breast is a very rare entity, which comprises only less than 0.5% of all breast malignancies. The follicular lymphoma of the breast is still rarer as the most common type is diffuse large B cell lymphoma (DLBCL). We are reporting two cases of follicular lymphoma of the breast. Methods/Case Report Case 1: A 67-year-old female with a history of low-grade follicular lymphoma of the lacrimal gland and cervical lymph node was presented with 1.7 cm irregular soft tissue mass in the upper inner quadrant of left breast identified on CT scan. Microscopic examination showed diffuse infiltration of medium-sized lymphocytes with focal follicular architecture. These lymphocytes were positive for CD20, CD10, BCL2, BCL6, and Ki67 (10%); while negative for CD5, CD3, cyclin D1, and EBER. These findings are consistent with low-grade follicular lymphoma. Subsequently, a biopsy of the right breast mass revealed similar findings. The patient was followed up with a PET scan every six months and doing well. Case 2: A 52-year-old female with a history of low-grade follicular lymphoma of the right hard/soft palate junction was presented with bilateral breast masses identified on mammography. The biopsy was performed and microscopic examination showed vaguely follicular architecture with small to medium-sized lymphocyte infiltration. The flow cytometric analysis revealed CD10 positive B cell population with kappa light chain restriction. Fluorescence in situ hybridization (FISH) analysis showed 96% of cells with BCL2 and BCL6 rearrangement. These findings were consistent with low-grade follicular lymphoma. The patient was started on chemotherapy with good outcomes. Results (if a Case Study enter NA) N/A Conclusion By reviewing two cases, we emphasize the rarity of follicular lymphoma in the breast. The most important differential diagnosis is extranodal marginal zone lymphoma and DLBCL. In absence of flow cytometric analysis FISH analysis for BCL-2 rearrangement or other molecular analysis is key to diagnose follicular lymphoma.

Racial and ethnic differences in all-cause mortality among Hispanics diagnosed with follicular lymphoma and chronic lymphocytic leukemia in the Bronx, NY.

Research suggests better survival among Hispanics with diffuse large B-cell lymphoma (DLBCL) compared to non-Hispanic Whites (NHW); however, less is known about racial/ethnic survival differences in follicular lymphoma (FL) and chronic lymphocytic leukemia (CLL). We identified incident FL and CLL cases diagnosed between 2005 and 2016 at Montefiore Medical Center in the Bronx, NY. Cox proportional hazards regression assessed the association between race/ethnicity and all-cause mortality among FL and CLL separately. Of the 201 FL patients, 39.3% were NHW, 19.4% non-Hispanic Black (NHB), and 41.3% Hispanic, with a similar distribution among CLL patients. After adjusting for International Prognostic Index factors, sex, and chemotherapy, Hispanics with FL had lower all-cause mortality compared to NHWs (HR = 0.22; 95% CI 0.08-0.63), similar to prior DLBCL findings. All-cause mortality did not differ between NHBs and NHWs for FL or by any race/ethnicity for CLL. In our diverse, urban population, we found that Hispanic diagnosed with FL had lower all-cause mortality compared to NHWs. We found no significant difference in all-cause mortality between Hispanics and NHWs diagnosed with CLL. Our study adds to the growing literature on racial and ethnic differences in survival among Hispanics with hematologic malignancies.

AN UNEXPECTED ETIOLOGY OF RESPIRATORY FAILURE DURING COVID-19 PANDEMIC

TOPIC: Chest Infections TYPE: Medical Student/Resident Case Reports INTRODUCTION: As a result of the pandemic, anchoring and premature closure on the novel virus as the etiology for a patient's shortness of breath is prevalent. We present an interesting case of concurrent follicular lymphoma and acute disseminated histoplasmosis in a HIV-negative patient that was admitted as COVID-19 pneumonia. CASE PRESENTATION: 83 year old negative HIV status Philippino male with tobacco abuse, recent diagnosis of pulmonary adenocarcinoma and pancreatic mass status post distal pancreatectomy with splenectomy presented with worsening dyspnea and admitted for acute hypoxic respiratory failure with oxygen saturations 79% on room air. He tested positive for COVID-19 six days prior. He was treated as COVID-19 pneumonia with Dexamethasone and Remdesivir. During his hospitalization, the outpatient pathology results from splenic tissue showed grade 3A follicular lymphoma and necrotizing granulomas consistent with Histoplasmosis. He was started on Amphotericin B and transitioned to oral Itraconazole due to acute kidney injury. Management of his pulmonary adenocarcinoma and follicular lymphoma were concomitantly followed up as outpatient oncology with plans to initiate radiation and rituximab. DISCUSSION: Follicular lymphoma and disseminated histoplasmosis are both rare, accounting for about 5% of hematological neoplasms and approximately 0.05% of acute infections, respectively. Patients diagnosed with these two disease states concomitantly are extremely rare. Immunosuppression increases the risk for acute infection and presentations often resemble other common conditions. Pulmonary imaging may be unrevealing in 10-50% of disseminated histoplasmosis cases. Gastrointestinal histoplasmosis is most commonly reported in the small intestine and colon, though can be seen in reticuloendothelial organs such as the spleen. The mortality of untreated disseminated histoplasmosis is 80%, but decreases substantially to 25% when treated. In addition, follicular lymphoma has largely favorable outcomes when treated. Early detection is critical in patients with either of these conditions to reduce morbidity and mortality. CONCLUSIONS: While many patients developed respiratory failure secondary to COVID-19, other etiologies of respiratory failure are still plausible. It is imperative for physicians to develop broad differential diagnoses on admission and reassess those differentials when patients do not respond to standard of care to reduce delay in making the correct diagnosis and reduce exposure to unnecessary treatments. REFERENCE #1: Aggarwal A, Garg S. Isolated Pancreatic Histoplasmosis: An Unusual Suspect of Pancreatic Head Mass in an Immunocompetent Host. Perm J. 2015;19(4):e145-e147. doi:10.7812/tpp/14-238 REFERENCE #2: Carbone A, Roulland S, Gloghini A, Younes A, von Keudell G, Lopez-Guillermo A, Fitzgibbon J. Follicular lymphoma. Nat Rev Dis Primers. 2019 Dec 12;5(1):83. doi: 10.1038/s41572-019-0132-x. PMID: 31831752. REFERENCE #3: Kahi CJ, Wheat LJ, Allen SD, Sarosi GA. Gastrointestinal histoplasmosis. Am J Gastroenterol. 2005 Jan;100(1):220-31. doi: 10.1111/j.1572-0241.2005.40823.x. PMID: 15654803. DISCLOSURES: No relevant relationships by Robert Blessing, source=Web Response No relevant relationships by Alyson Bundy, source=Web Response No relevant relationships by jennifer mundell, source=Web Response

S3687 Rare Case of Extra Nodal Follicular B-cell Lymphoma of Small Intestine Presenting With Weight Loss

S3687 Rare Case of Extra Nodal Follicular B-cell Lymphoma of Small Intestine Presenting With Weight Loss

S2246 Gastrointestinal Follicular Lymphoma: Cases Series and Management Approach

Introduction: Follicular lymphoma (FL) is the second most common subtype of non- Hodgkin lymphoma (NHL). In the gastrointestinal (GI) tract, it accounts for 1-3% of GI malignancies. A clear distinction between primary FL of the GI tract and disseminated FL with GI involvement should be made. The duodenum is the most common site involved, followed by the ileum and the colon. We present three cases of GI follicular lymphoma with unique diagnostic and management approaches. Case Description/Methods: A 54-year-old man presented for a screening colonoscopy. Physical examination and laboratory data were unremarkable. Colonoscopy showed two polyps in the transverse colon. Pathology was consistent with low grade follicular lymphoma. Positron emission tomography (PET) scan was unremarkable. Patient remained asymptomatic on follow-up visits with normal blood work. A 42-year-old female presented with epigastric abdominal pain. Physical exam revealed tenderness to palpation in the epigastrium.Laboratory findings: white blood cell count, 16.8x10(3) mcL. CT showed a mass in the duodenum at the level of the ampulla. EGD showed a 0.8cmx2cm mass in the 2nd portion of duodenum. Pathology was consistent with follicular lymphoma. Patient underwent treatment with chemotherapy for 3 months with remission, and no recurrence. A 73-year-old female presented for a routine screening colonoscopy. Physical examination and laboratory data were unremarkable. Colonoscopy showed hyperplastic, non-bleeding polyps in the terminal ileum. Pathology was consistent with high grade follicular lymphoma. Imaging with CT scan and PET scan were performed with no findings of gross adenopathy or extra nodal involvement. Patient underwent treatment with chemotherapy for 5 months with remission, and no recurrence. Discussion: Tumors originate from germinal center B cells; both centrocytes and centroblasts. Clinical presentation is variable. It is crucial to differentiate whether follicular lymphoma arises primarily from the GI tract, or is a result of disseminated disease. Endoscopy is useful for direct visualization of the GI tract and biopsy. Diagnosis is based on histology, immunophenotyping, bcl-2 protein expression in cells and detection of the t(14;18) translocation by PCR. Management of FL of GI tract is not well established due to rarity of the disease. Monitoring should be conducted via clinic visits, blood work, and cross-sectional imaging CT/PET scan. Treatment should be tailored to each patient’s unique presentation and disease activity.Figure 1.: (A) Abdominal radiograph shows two apposed metallic circular objects projecting over the right hemiabdomen and pan-colonic gaseous dilation without evidence of small bowel obstruction. (B) Colonoscopy images show a penny and shard of glass partially obstructing the opening of the ileocecal valve as well as (C) a dime lodged just proximally to the penny within the ileocecal valve. (D) Rat tooth forceps were used to remove the coins from the ileocecal valve and place them in the cecum for (E) safe and complete removal of the objects from the colon with a Roth net. (F) A penny, dime, and two shards of glass were ultimately retrieved.

Transformation of low-grade follicular lymphoma with partial marginal zone differentiation: Two cases.

Two cases of low-grade follicular lymphoma, with marginal zone differentiation and/or with high proliferation rate in one of them, are reported with transformation into high grade B-cell and B-lymphoblastic lymphomas. The contribution of these features to the transforming process, although previously described, is infrequent, and has not been deciphered to date.

Epidemiology of diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma (FL) in the United States and Western Europe: population-level projections for 2020–2025

Diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma (FL) treatments have been rapidly evolving for patients treated in later lines of therapy (LoT). Country-specific cancer registry data for the US and Western Europe (WE) were combined with physician survey results to project the incidence, prevalence, and number of DLBCL and FL patients eligible for and treated by LoT between 2020 and 2025. The total number of incidents and prevalent cases of DLBCL and FL is expected to increase between 2020 and 2025 in the US and WE. 56% and 53% of the third line plus (3L+) eligible DLBCL patients and 60% and 55% of eligible FL patients initiated treatment in the US and WE, respectively. Further research is warranted to understand the reasons behind the high proportion of treatment eligible patients who do not initiate treatment, and potential differences between countries, especially in the 3L + settings.

The first case of methotrexate‐associated lymphoproliferative disorder presenting as follicular T‐cell lymphoma

This is the first case of follicular T-cell lymphoma (FTCL) presenting as methotrexate-associated lymphoproliferative disorders (MTX-LPDs). A 69-year-old man treated rheumatoid arthritis with methotrexate presented with cervical swelling, hoarseness and fever. Imaging studies revealed multiple lymphadenopathy and lymphoma was suspected. Lymph node biopsy was performed to confirm the diagnosis. Pathologically, the lymph node was composed of atypical lymphocytes with a follicular growth pattern and area of necrosis. Immunohistochemical examination showed the atypical lymphocytes were positive for CD3, CD4, programmed cell death protein 1, and inducible T-cell co-stimulator. These findings are consistent with FTCL. During hospitalization, the patient's fever subsided and cervical lymphadenopathy improved, probably due to discontinuation of MTX. Here we presented the first case of FTCL presenting as MTX-LPDs. The T-cell phenotype MTX-LPDs are relatively rare and accounts for only 3.4%-6.3% of all MTX-LPD cases. Therefore, detailed clinicopathological features have not been clarified sufficiently. It is hoped that similar cases should be accumulated and studied to better understand the clinical and pathological features of this condition.

IBCL-263: Prognostic Significance of CD23 Expression Pattern in Follicular Lymphoma Morphological Grades

<h3>Context</h3> CD23 expression in follicular lymphoma (FL) is associated with better overall survival (OS). It is known that FL cases with inguinal lymph node lesions and large-cell morphology are characterized by CD23 expression, which is a distinctive feature of these patients whose prognosis is also favorable. However, the CD23 prognostic significance in various FL morphological grades and other tumor lesion localization is unclear. <h3>Objective</h3> To determine the CD23 expression prognostic value in different FL grades. <h3>Design</h3> CD23 expression pattern was evaluated by immunohistochemistry. Three groups of patients were identified: expression is absent (CD23neg), intense expression in all cells (CD23bright), expression is weak and/or only present in a portion of tumor cells (CD23dim). <h3>Patients</h3> The study included 206 FL patients, including 93 FL1–2 grade, 68 FL3A, 45 FL3B, and transformation into DLBCL. In 102 patients, inguinal region involvement was noted. <h3>Results</h3> In general, OS was similar for the CD23neg, CD23bright, and CD23dim groups. There was also no correlation between OS and CD23 expression in patients with and without iliac region involvement. However, we found that CD23 prognostic value depends on FL grade. In FL1–2 and aggressive FL, there was no association between OS and CD23 expression. In FL3A patients, OS in the CD23dim group was lower than in the CD23neg and CD23 bright groups. The 5-year OS in the CD23neg, CD23bright, and CD23dim groups were 91%, 87%, and 65%, respectively. The level of these differences tended to be significant (log-rank test, p=0.09). <h3>Conclusions</h3> The previously shown association between CD23 expression, lesion localization, and OS was not confirmed. However, CD23 expression pattern analysis revealed a fact not previously known. The intermediate CD23 expression pattern is an unfavorable prognostic factor in FL3A patients. It is worth noting that combining CD23dim with CD23neg into a single group resulted in a "favorable" status compared with the CD23bright group. Thus, expression cutoff is important, and we assume this phenomenon has not been previously noted because the true CD23bright value was not identified. The heterogeneous CD23 expression in the tumor population probably indicates clonal tumor heterogeneity, which correlates with an unfavorable disease course.

A case of follicular lymphoma occurring as an early symptom in the cheek of an HTLV-1-carrier

A case of follicular lymphoma occurring as an early symptom in the cheek of an HTLV-1-carrier

Lymphoma of the Lacrimal Sac: The Massachusetts Eye and Ear Experience With a Comparison to the Previously Reported Literature.

To describe the frequency, clinical features, and histologic subtypes of biopsy proven lacrimal sac lymphomas, and to compare these results to the previously published literature. A retrospective chart review was performed at a single institution from 2004 to 2017. Pathology reports, operative notes, and patients' medical charts were reviewed. Of 566 lacrimal sacs submitted for routine histopathologic evaluation, 16 cases of lymphoma were identified. All were low-grade, non-Hodgkin B-cell lymphomas, biopsied at an average age of 71 years. Thirteen patients (81.25%) had a pre-existing lymphoma diagnosis; the average interval between the diagnosis of systemic or nonocular adnexal lymphoma and lacrimal sac lymphoma was 7.9 years (range 2-26 years; median 5.5 years). Three cases of primary lacrimal sac lymphoma were identified. Histopathology showed 3 cases (18.75%) of follicular lymphoma, 3 (18.75%) of extranodal marginal zone lymphoma, and 10 (62.5%) of chronic lymphocytic leukemia/small lymphocytic lymphoma. Primary cases presented with epiphora and nasolacrimal duct obstruction, while secondary cases predominantly manifested as dacryocystitis. All lacrimal sac neoplasms were locally responsive (without local recurrence) to chemotherapy, radiation, or both. Lacrimal sac lymphoma is uncommon but should be suspected among patients with known lymphoma who develop dacryocystitis. In this series, primary lacrimal sac lymphoma most often presented as a mass or nasolacrimal duct obstruction. Chronic lymphocytic leukemia/small lymphocytic lymphoma was the most commonly identified cause of secondary lacrimal sac lymphoma. Distinguishing primary from secondary lacrimal sac lymphomas is important, as the extent of disease and histopathologic subtypes differ, which may affect patient management.

Small intestinal follicular lymphoma induced by methotrexate: a case report

BackgroundMethotrexate-associated lymphoproliferative disorder (MTX-LPD) is a rare but critical complication that develops in patients treated with MTX. Although MTX-LPD has been recently reported, the incidence of follicular lymphoma in the intestine is very low.Case presentationA 73-year-old woman who had been receiving MTX for over 10 years visited our hospital complaining of postprandial abdominal pain and nausea. Upper and lower digestive tract endoscopies did not show any abnormal findings. A patency capsule was stagnated at the proximal part of the ileum with a mild dilation on the oral side. An oral balloon endoscopy revealed shallow ulcerative lesions in the jejunum. She was diagnosed with MTX-LPD based on histopathological findings. The symptoms did not improve with the discontinuation of MTX, and the patient required partial resection of the small intestine. The test result for Epstein-Barr virus-encoded small RNA was negative. She was diagnosed with follicular lymphoma based on the histology findings of a surgical specimen. Postoperative positron emission tomography-computed tomography and bone marrow aspiration did not show any findings of lymphoma. On follow-up, no recurrence was noted four years after the surgery.ConclusionsHerein, we report the first case of follicular lymphoma that occurred in the small intestine, negative for Epstein-Barr virus-encoded small RNA. If intestinal symptoms occur during MTX administration, it is important to directly observe by endoscopy and perform histological examination.

Abstract 1939: Follicular Lymphoma-associated mutations in the V-ATPase assembly factor VMA21 activate autophagic flux

Abstract Introduction: Follicular lymphoma (FL) constitutes the second most common non-Hodgkin lymphoma in the Western world. FL carries a high incidence of gene mutations in various V-ATPase subunits and regulators (ATP6V1B2, ATP6AP1, and VMA21) accounting for a combined 25-30% of FL cases. We have previously demonstrated that an FL-associated mutation in the V-ATPase V1 subunit ATP6V1B2 induces autophagic flux, thus conferring a survival addiction on mutated FL B cells. Here, we report results from functional analysis of the common hotspot truncating mutations p.R93* in the V-ATPase assembly factor VMA21 in FL. Methods: We measured autophagic flux using a variety of complementary assays in recombinant cell lines expressing inducible VMA21 WT and MUT (p.R93*). Lysosome acidification was measured using pH-sensitive dyes linked to dextran and flow-cytometry. The subcellular localization of VAM21 was investigated using confocal microscopy. The VMA21 WT and MUT-associated proteome was analyzed using immunoprecipitation followed by quantitative mass spectrometry-based protein profiling (IP-MS). Results: The inducible expression of VMA21 p.R93* activated autophagic flux as measured through various assays, including: i) increased autolysosome numbers measured via electron microscopy, ii) elevated LC3-II and elevated free GFP in HEK293T and lymphoma cells expressing a GFP-LC3-RFP probe, iii) elevated autophagosomes and autolysosomes detected via confocal microscopy in HEK293T cells, which were ablated by ULK1 and PIK3C3/VPS34 inhibitors, iv) elevated autophagic flux in various yeast assays. The inducible expression of mutant VMA21 partially impaired lysosomal acidification, implicating inhibitory effects on the V-ATPase holoenzyme. Analysis of subcellular localization of WT and MUT VMA21 using lysosomal-IPs and confocal microscopy showed that VMA21 MUT mislocalized to lysosomes and did not shuttle back to the ER. Using quantitative IP-MS, we detected elevated amounts of V-ATPase components in the VMA21 MUT immunoprecipitates, indicating increased complex formation between MUT VMA21 and fully assembled V-ATPase. Studies are underway measuring V-ATPase activity in lysosomes in VMA21 WT and MUT cells and effects on the lysosomal metabolome. In addition, we are testing the effects of small molecule autophagy inhibitors on the survival of VMA21 MUT primary FL cells. Conclusion: Our data support the hypothesis that the FL-associated VMA21 p.R93* has altered subcellular trafficking. As a consequence, more MUT VMA21 associates with the V-ATPase holoenzyme resulting in partial impairment of V-ATPase activity. Similar to our previous findings on ATP6V1B2 mutations, the MUT VMA21 aberrantly activates autophagic flux possibly as compensation to impaired V-ATPase function. This study supports future investigations into therapeutic targeting of aberrantly activated autophagy in FL. Citation Format: Fangyang Wang, Ying Yang, Gabriel Boudagh, Eeva-Liisa Eskelinen, Daniel J. Klionsky, Sami N. Malek. Follicular Lymphoma-associated mutations in the V-ATPase assembly factor VMA21 activate autophagic flux [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1939.

Issue Highlights-July 2021.

Issue Highlights-July 2021.

Effect of Histologic Grade on Clinical Outcomes of Follicular Lymphoma: Prolonged Progression Free Survival of Grade 3 Follicular Lymphoma in the Rituximab Era

Introduction: Follicular lymphoma(FL) is a heterogeneous lymphoid malignancy that can be further sub classified into grades 1, 2, 3A and 3B, based on the percentage of centroblasts per high power field. Historically, grade 3A FL has been considered to have a biological and clinical profile akin to grades 1-2 FL whereas grade 3B FL is considered to have a clinical presentation and treatment outcome similar to diffuse large B cell lymphoma (DLBCL). We examine the impact of FL grading and sub classification on initial treatment choice and outcomes in a cohort of FL subjects diagnosed in the rituximab era.Methods: We accessed the Hematological Malignancies database of University Hospitals Seidman Cancer Center to retrieve data on FL patients (pts) diagnosed between 2002 and 2014. Demographic data, laboratory and disease characteristics were recorded. We excluded pts with incomplete follow up data and any unclassified FL cases. Biopsies from all available grade 3 FL cases were reviewed by a hematopathologist for sub classification into grade 3A or 3B FL categories. The outcomes of grade 3 FL patient cohort were separately compared with contemporaneous cohorts of patients diagnosed with grade 1-2 FL and germinal center B cell (GCB) subtype of DLBCL. The Kaplan-Meier method was used to assess overall survival (OS) and progression-free survival (PFS). Two-tailed log-rank test compared OS and PFS curves. All analyses were performed using IBM SPSS Statistics 2015.Results: We identified 227 FL pts with complete clinical information. Approximately one third of pts (n=62, 27%) had grade 3 FL (grade 3A, n = 35, grade 3B, n = 24; unclassified, n = 2). Comparisons between baseline characteristics and initial therapy of grade 1-2 FL and grade 3 FL are presented in Table 1. While baseline demographic characteristics were not different, the rate of transformation was higher in grade 3 FL. Use of cytotoxic chemo-immunotherapy and anthracycline was more common in grade 3 FL.Median OS was not reached for the whole FL cohort. We did not observe a statistically significant difference in OS between grade 1-2 FL and grade 3 FL. Grade 3 FL presented a higher PFS compared with grade 1-2 FL (5-year PFS 61% vs 41%, p=0.016) (Figure 1). To examine the effect of histologic grade on outcomes after therapy, we limited the analysis to subjects treated with chemo-immunotherapy as initial treatment: 5 year PFS was longer for patients diagnosed with grade 3 FL (61% vs 43 %, p=0.015). Limiting the analysis to subjects treated only with first line anthracycline-containing chemo-immunotherapy also demonstrated grade 3 FL presenting with a longer PFS (5-year PFS 61 % vs 31 %, p<0.001). Further subgroup analysis comparing only grade 3A FL (n=35) pts with the anthracycline treated grade 1-2 FL (n=57) demonstrated longer 5-year PFS in the grade 3A cohort (p<0.001). (Figure 2). Consistent with previous reports, there were no differences in baseline clinical features, PFS or OS between the grade 3A and grade 3B FL patient cohorts. Further comparison of outcomes of grade 3A FL in our cohort had a similar PFS to GCB DLBCL (5 year PFS 62% vs 56 %, p=0.188).Conclusion: In this retrospective study of outcomes of follicular lymphoma in the rituximab era, we observed that patients diagnosed with grade 3 FL have better PFS than patients diagnosed with lower grade FL. This improved outcome appears to be independent of the choice of initial therapy, with an apparent plateau in the risk of relapse of patients diagnosed with grade 3A FL, suggesting a subgroup of these subjects can receive front line treatment with curative intent. [Display omitted] DisclosuresMalek:Takeda: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Sanofi: Membership on an entity's Board of Directors or advisory committees; Celgene: Speakers Bureau. Cooper:Novartis: Research Funding. de Lima:Pfizer: Membership on an entity's Board of Directors or advisory committees; Celgene Corporation: Research Funding. Caimi:Abbvie: Equity Ownership; Seattle Genetics: Equity Ownership; Incyte: Equity Ownership; Celgene: Speakers Bureau.

Aberrant Activation of NF-κB and Hypoxia Enhances Glycolytic Enzyme Hexokinase II Expression in B-Cell Lymphoma through Activation of HIF-1

Malignant lymphoma cells tend to use glycolysis for the production of ATP even with a substantial oxygen supply, a process known as aerobic glycolysis that is illustrated by a high uptake of FDG-glucose. Though elevated levels of glycolytic enzymes are responsible for aerobic glycolysis, the precise molecular mechanisms of this process are not well understood. In physiological conditions, the expression of glycolytic enzymes is mainly regulated by hypoxia inducible factor (HIF). Previously, we revealed that the aberrant activation of NF-κB causes the activation of HIF pathways in B-cell lymphoma (Exp.Hematology, 2010 &2013). It is widely accepted that abnormal activation of NF-κB is one of the hallmarks of B-cell lymphoma. Based on these notions, in the present study, we analyzed the possible link between aberrant activation of NF-κB, HIF and enhanced glycolysis in lymphoma cells. We also investigated the possibility that the inhibition of enhanced glycolysis could be a therapeutic target in lymphoma.For this study, we used a series of B-cell lymphoma cell lines. Under basal conditions, these cells display aberrant NF-κB activation and expression of the alpha subunit of HIF-1 (HIF-1α). Of the glycolytic enzymes, hexokinase II (HXKII) levels were specifically elevated in these cells. To confirm that aberrant activation of NF-κB was responsible for the elevation of HIF-1α and HXKII, we treated the cells with several NF-κB inhibitors. The NF-κB inhibitors clearly suppressed the expression of both HIF-1α and HXKII. Inhibition of HIF-1 by panobinostat also led to decreased HXKII levels. Panobinostat also suppressed hypoxia-induced HIF-1α and HXKII elevation. We further analyzed HXKII expression in biopsy specimens from newly diagnosed B-cell lymphoma cases after receiving approval from an institutional review board and acquisition of written informed consent. We analyzed 6 cases of diffuse large B-cell lymphoma (DLBCL), 3 cases of follicular lymphoma (FL) and 1 case of mantle cell lymphoma. HXKII expression was detected in 5 of the 6 DLBCL cases but not in the FL cases. Interestingly, according to Hans classification, the HXKII-positive DLBCL cases were non-GCB types.Finally, we explored the possibility that inhibition of HXKII could enhance the activity of anti-lymphoma chemotherapeutic drugs. We confirmed that hypoxia diminished the anti-lymphoma action of several chemotherapeutic drugs, including cisplatin. To investigate whether inhibition of HXKII could overcome the reduced anti-lymphoma action of these reagents, we treated the cells with either 2-deoxy-glucose or clotrimazole, which are both inhibitors for HXKII. We found that these reagents reversed the anti-lymphoma activity of cisplatin, even during hypoxia. Panobinostat also restored cisplatin-induced apoptosis in B-cell lymphoma cells during hypoxia.In conclusion, our present findings reveal that expression of glycolytic enzyme HXKII was elevated in B-cell lymphoma cells, and two distinct mechanisms, aberrant activation of NF-κB and a hypoxic microenvironment, induce HXKII elevation through activation of HIF-1. This work also suggests that the axis between HIF-1 and HXKII might be an attractive therapeutic target for B-cell lymphomas, especially those with aberrant NF-κB activity. DisclosuresKirito:Novartis Pharma KK: Honoraria.