Pathology and diagnosis of follicular lymphoma and related entities

Unraveling the complexity of follicular lymphoma: insights and innovations

This review discusses multiple aspects of follicular lymphoma (FL), including etiology, treatment challenges, and future perspectives. First, we delve into the etiology of FL, which involves a variety of pathogenic mechanisms such as gene mutations, chromosomal abnormalities, immune escape, immune system dysregulation, familial inheritance, and environmental factors. These mechanisms provide the context for understanding the diversity and complexity of FL. Second, we discuss the challenges faced when treating FL, particularly treatment resistance. Therapeutic resistance is a common problem in treatment, but by delving into the mechanisms of resistance, scientists have looked for strategies to combat it, including developing new drugs, improving treatments, and exploring combination therapy strategies. We also emphasize the breakthroughs in molecular biology, especially the study of targeting the BCL2 gene, which provides a new direction for targeted therapy in FL. Immunotherapy, small molecule targeted drugs, and individualized treatment strategies are also promising for the future treatment of FL. Finally, we look to the future, including research on therapeutic resistance, in-depth studies of genetics and gene expression, applications of gene editing and precision medicine, and clinical trials of new treatments. These lines of research offer additional opportunities for treating FL, and despite the challenges, the future is promising. This literature review provides comprehensive and integrated information for the in-depth understanding of FL and relevant treatment approaches.

A genetic profiling guideline to support diagnosis and clinical management of lymphomas

The new lymphoma classifications (International Consensus Classification of Mature Lymphoid Neoplasms, and 5th World Health Organization Classification of Lymphoid Neoplasms) include genetics as an integral part of lymphoma diagnosis, allowing better lymphoma subclassification, patient risk stratification, and prediction of treatment response. Lymphomas are characterized by very few recurrent and disease-specific mutations, and most entities have a heterogenous genetic landscape with a long tail of recurrently mutated genes. Most of these occur at low frequencies, reflecting the clinical heterogeneity of lymphomas. Multiple studies have identified genetic markers that improve diagnostics and prognostication, and next-generation sequencing is becoming an essential tool in the clinical laboratory. This review provides a "next-generation sequencing" guide for lymphomas. It discusses the genetic alterations of the most frequent mature lymphoma entities with diagnostic, prognostic, and predictive potential and proposes targeted sequencing panels to detect mutations and copy-number alterations for B- and NK/T-cell lymphomas.

A review on human cancer and potential role of MXenes in cancer therapy

Cancer is the second leading cause of death worldwide and is having a serious impact on the global economy. Various treatment modalities are in use to treat cancer but none of the techniques is risk-free. Recently, various nanomaterials such as gold, boron, and other compounds have been investigated for radiotherapy and as anti-cancer drug carriers with promising results. MXenes are 2D novel nanomaterials and their biomedical and anticancer properties are gaining interest due to their high biomedical activity, less bio-toxicity, and photo-responsive nature. However, the biological properties of MXense have not been studied extensively, therefore, limited data is published on its in-vitro and in-vivo anticancer activities, drug loading efficacy, targeted release, and on its photothermal therapy response. In this review, we have discussed the use of nanoparticles and MXenen nanomaterial in cancer therapy. Furthermore, the role of Mxene as a photothermal agent and drug carrier has also been emphasized, along with the present challenges for the use of nanomaterials in the treatment of cancer.

Analysis of immunophenotypic features in hyaline vascular type Castleman disease

BACKGROUND

Studies suggested that the immunophenotype of hyaline vascular type Castleman disease (HVCD) lacked characteristics, which was easy to be confused with other diseases.

METHODS

From January 2010 to June 2022, 17 cases of HVCD were selected from the Department of Pathology of Shaanxi Provincial People's Hospital and the Department of Pathology of Shaanxi Provincial Cancer Hospital. 13 cases of reactive hyperplastic lymph nodes (RHL) and 11 cases of follicular lymphoma (FL) were selected as the control group. All cases were performed CD3, CD20, CD21 and BCL2 immunohistochemical staining.

RESULTS

(i) In 17 cases of HVCD, the negative area of BCL2 of germinal center was significantly smaller than the negative area of CD3 of germinal center. However, in 13 cases of RHL, the negative area of CD3 of germinal center was basically consistent with the negative area of germinal center of BCL2 of germinal center. In 11 cases of FL, in neoplastic follicles, the negative area of CD3 was basically consistent with the positive area of BCL2. The difference between HVCD group and other two groups of diseases was statistically significant (P < 0.05). (ii) In 17 cases of HVCD, the negative area of BCL2 of germinal center was significantly smaller than the follicular dendritic cell (FDC) meshworks expressed by CD21. However, in 13 cases of RHL, the FDC meshworks expressed by CD21 were basically consistent with the negative area of BCL2 of germinal center. In 11 cases of FL, in neoplastic follicles, the FDC meshworks expressed by CD21 was basically consistent with the positive area of BCL2. The difference between HVCD group and other two groups of disease was statistically significant (P < 0.05).

CONCLUSIONS

HVCD has unique immunophenotypic characteristics. The negative area of BCL2 of germinal center is significantly smaller than the negative area of CD3. The negative area of the BCL2 of germinal center is significantly smaller than the FDC meshworks expressed by CD21. These two immunophenotypic features in HVCD are very important in diagnosis and differential diagnosis.

Raptor mediates the selective inhibitory effect of cardamonin on RRAGC-mutant B cell lymphoma

BACKGROUND

mTORC1 (mechanistic target of rapamycin complex 1) is associated with lymphoma progression. Oncogenic RRAGC (Rag guanosine triphosphatase C) mutations identified in patients with follicular lymphoma facilitate the interaction between Raptor (regulatory protein associated with mTOR) and Rag GTPase. It promotes the activation of mTORC1 and accelerates lymphomagenesis. Cardamonin inhibits mTORC1 by decreasing the protein level of Raptor. In the present study, we investigated the inhibitory effect and possible mechanism of action of cardamonin in RRAGC-mutant lymphoma. This could provide a precise targeted therapy for lymphoma with RRAGC mutations.

METHODS

Cell viability was measured using a cell counting kit-8 (CCK-8) assay. Protein expression and phosphorylation levels were determined using western blotting. The interactions of mTOR and Raptor with RagC were determined by co-immunoprecipitation. Cells overexpressing RagC wild-type (RagCWT) and RagC Thr90Asn (RagCT90N) were generated by lentiviral infection. Raptor knockdown was performed by lentivirus-mediated shRNA transduction. The in vivo anti-tumour effect of cardamonin was assessed in a xenograft model.

RESULTS

Cardamonin disrupted mTOR complex interactions by decreasing Raptor protein levels. RagCT90N overexpression via lentiviral infection increased cell proliferation and mTORC1 activation. The viability and tumour growth rate of RagCT90N-mutant cells were more sensitive to cardamonin treatment than those of normal and RagCWT cells. Cardamonin also exhibited a stronger inhibitory effect on the phosphorylation of mTOR and p70 S6 kinase 1 in RagCT90N-mutant cells. Raptor knockdown abolishes the inhibitory effects of cardamonin on mTOR. An in vivo xenograft model demonstrated that the RagCT90N-mutant showed significantly higher sensitivity to cardamonin treatment.

CONCLUSIONS

Cardamonin exerts selective therapeutic effects on RagCT90N-mutant cells. Cardamonin can serve as a drug for individualised therapy for follicular lymphoma with RRAGC mutations.

Follicular lymphoma: an update on biology and optimal therapy

Follicular lymphoma (FL) is a mature B-cell neoplasm with a mostly indolent course. Genetic hallmark characteristics are Bcl-2 overexpression based on a t(14;18) translocation and additional secondary genetic and epigenetic aberrations. Standard treatment for early-stage patients has curative intent and usually consists of radiotherapy with or without rituximab. In the advanced stage, the main therapeutic focus is on prolonged remissions. Therefore, treatment in asymptomatic patients is usually deferred. Symptomatic patients are subject to immunochemotherapy induction followed by antibody maintenance. Importantly, about one in five patients subsequently experiences a more rapid clinical course, achieving only short remissions with multiple relapses (POD24). In those patients, there is still an urgent need for improved therapeutic options. Accordingly, a plethora of targeted and immunotherapeutic options, including immunomodulatory drugs, small molecule inhibitors, monoclonal antibodies as well as bispecific T-cell engager antibodies and CAR-T cell products have been recently evaluated in such relapsed high-risk patients.

Artificial Intelligence Predicted Overall Survival and Classified Mature B-Cell Neoplasms Based on Immuno-Oncology and Immune Checkpoint Panels

Artificial intelligence (AI) can identify actionable oncology biomarkers. This research integrates our previous analyses of non-Hodgkin lymphoma. We used gene expression and immunohistochemical data, focusing on the immune checkpoint, and added a new analysis of macrophages, including 3D rendering. The AI comprised machine learning (C5, Bayesian network, C&R, CHAID, discriminant analysis, KNN, logistic regression, LSVM, Quest, random forest, random trees, SVM, tree-AS, and XGBoost linear and tree) and artificial neural networks (multilayer perceptron and radial basis function). The series included chronic lymphocytic leukemia, mantle cell lymphoma, follicular lymphoma, Burkitt, diffuse large B-cell lymphoma, marginal zone lymphoma, and multiple myeloma, as well as acute myeloid leukemia and pan-cancer series. AI classified lymphoma subtypes and predicted overall survival accurately. Oncogenes and tumor suppressor genes were highlighted (MYC, BCL2, and TP53), along with immune microenvironment markers of tumor-associated macrophages (M2-like TAMs), T-cells and regulatory T lymphocytes (Tregs) (CD68, CD163, MARCO, CSF1R, CSF1, PD-L1/CD274, SIRPA, CD85A/LILRB3, CD47, IL10, TNFRSF14/HVEM, TNFAIP8, IKAROS, STAT3, NFKB, MAPK, PD-1/PDCD1, BTLA, and FOXP3), apoptosis (BCL2, CASP3, CASP8, PARP, and pathway-related MDM2, E2F1, CDK6, MYB, and LMO2), and metabolism (ENO3, GGA3). In conclusion, AI with immuno-oncology markers is a powerful predictive tool. Additionally, a review of recent literature was made.

The prognostic nutritional index, an independent predictor of overall survival for newly diagnosed follicular lymphoma in China

Objective

The prognostic nutritional index (PNI) is an important prognostic factor for survival outcomes in various hematological malignancies. The current study focused on exploring the predictive value of the PNI in newly diagnosed follicular lymphoma (FL) in China.

Materials and methods

The clinical indicators and follow-up data of 176 patients who received chemotherapy or immunotherapy combined with chemotherapy with FL in our hospital from January 2016 to March 2022 were retrospectively analyzed. Cox proportional hazard model was used for univariate and multivariate analyses. Kaplan–Meier curves were used to calculate survival rates and draw survival curves. The log-rank test was applied to compare differences between groups.

Results

The optimal cut-off value of PNI was 44.3. All patients were divided into a high PNI group (>44.3) and a low PNI group (≤44.3). The low PNI group had a low CR rate and a high risk of death, with a tendency toward POD24, and Both OS and PFS were worse than those in the high PNI group. PNI was able to predict OS and PFS in FL patients and was the only independent predictor of OS (P = 0.014 HR 5.024; 95%CI 1.388∼18.178) in multivariate analysis. PNI could re-stratify patients into groups of high FLIPI score, high FLIPI2 score, no POD24, and rituximab combined with chemotherapy. Moreover, integrating PNI into the FLIPI and FLIPI2 models improved the area under the curve (AUC) for more accurate survival prediction and prognosis.

Conclusion

PNI is a significant prognostic indicator for newly diagnosed FL in China that can early identify patients with poor prognosis and guide clinical treatment decisions.

Ascites as First Atypical and Only Clinical Manifestation of De Novo Follicular Lymphoma

Follicular lymphoma is the most common indolent non-Hodgkin’s lymphoma and is usually initially detected in lymph nodes. Primary extranodal NHL is most commonly primarily localized in the gastrointestinal tract. We present one unusual case of ileum FL with ascites as the first clinical sign. The 73-year-old female patient was presented to the emergency department for evaluation of mild abdominal pain and abdominal swelling that had been going on for three days followed by bloating and occasional pain in the spine. The abdominal contrast-enhanced CT revealed the contrast stagnation in the distal part of the ileum. The ileum wall about 11 cm in length was thickened up to 2.9 cm and the tumor mass infiltrated all layers of ileum mesenteric lymphadenopathy up to 2 cm in diameter and significant ascites. On the upper ileum wall, the vegetative mass was described 3 cm in diameter. The patient had an emergent laparotomy with the ileocolic resection and latero-lateral ileocolic anastomosis. The microscopy finding of terminal ileum and the regional lymph nodes showed domination of cleaved cells with irregular nuclei which correspond to centrocytes. There were 0–15 large non-cleaved cells corresponding to centroblast in the microscopy high-power field. The final diagnosis was follicular lymphoma, the clinical stage 2E and histological grade by Berard and Mann criteria 1–2.

Clinicopathological analysis of immunohistochemical expression of immune checkpoint molecules in follicular lymphoma

Follicular lymphoma (FL) is characterized by an indolent clinical course and a high relapse rate, and often exhibits a diffuse pattern beyond the follicular area. Our group previously reported that immune checkpoint (ICP) pathways, such as programmed cell death (PD-1) and programmed death ligand 1 (PD-L1), are poor prognostic factors for diffuse large B-cell lymphoma and adult T-cell leukemia/lymphoma.In this study, the association between the expression of multiple ICP molecules according to immunohistochemistry and clinicopathological features in FL was determined via immunostaining of 173 biopsy samples. Membrane and/or cytoplasm expression of CD86 (nCD86) and PD-L1 (nPD-L1) was found in tumor cells, whereas PD-1 (miPD-1), Galectin-9 (miGalectin-9), OX40 (miOX40), CTLA-4 (miCTLA-4), Tim-3 (miTim-3), OX40L (miOX40L), and LAG-3 (miLAG-3) were expressed in non-neoplastic stromal cells. MiPD-1 expression was significantly higher in the follicular area than in the diffuse area (p=0.0450). Expression of miOX40 and miCTLA-4 was significantly higher in the diffuse area than in the follicular area (respectively, p=0.0053 and p=0.0092). MiTim-3 tended to be higher in the diffuse area than in the follicular area (p=0.0616). MiTim-3 was significantly higher in relapse cases than in new-onset cases (p=0.0440); miLAG-3 tended to be higher in relapse cases than in new-onset cases (p=0.0622, not significant). The miOX40L-high FL group had a significantly worse overall survival than the miOX40L-low group (p=0.0320).The expression of multiple ICP molecules on several cells reflects activated anti-tumor immunity and the unique FL microenvironment. Further studies on gene expression or genomic abnormalities will reveal the clinical and biological significance of ICP molecules in FL. This article is protected by copyright. All rights reserved.

Molecular Update and Evolving Classification of Large B-Cell Lymphoma

Diffuse large B-cell lymphomas (DLBCLs) are aggressive B-cell neoplasms with considerable clinical, biologic, and pathologic diversity. The application of high throughput technologies to the study of lymphomas has yielded abundant molecular data leading to the identification of distinct molecular identities and novel pathogenetic pathways. In light of this new information, newly refined diagnostic criteria have been established in the fourth edition of the World Health Organization (WHO) consensus classification of lymphomas, which was revised in 2016. This article reviews the histopathological and molecular features of the various aggressive B-cell lymphoma subtypes included in the updated classification.

Primary cutaneous follicle center lymphoma in a 16-year-old girl

In the pediatric and adolescent age group, primary cutaneous lymphomas are rare, especially cutaneous B-cell lymphomas. According to the World Health Organization, the three main subtypes of primary cutaneous B-cell lymphomas are primary cutaneous marginal zone B-cell lymphoma (PCMZL), primary cutaneous follicle center lymphoma (PCFCL), and primary cutaneous diffuse large B-cell lymphoma, leg type. We present an extraordinary case of PCFCL arising in a 16-year-old female, only the sixth case of PCFCL to be reported in the literature in a patient less than 20 years old. Although PCMZL was considered in this case, the finding of lambda light chain restriction in the BCL-6 and CD10 positive population of lymphocytes established the diagnosis of primary cutaneous follicle center lymphoma. Not many data currently exist on the prognosis of PCFCL in young individuals, but adult PCFCL has a good prognosis with an indolent course and 5-year survival rates over 95%. Because of its uncommon manifestation in young patients, the diagnosis of PCFCL is often delayed or missed. This case is presented to raise awareness of PCFCL in the pediatric/ adolescent population and to contribute to the ongoing research of this condition.

Primary cutaneous follicle center lymphoma with extensive plasmacytic differentiation and t(14;18) in both the lymphoid and plasma cell components

Primary cutaneous follicle center lymphoma (PCFCL) is the most common cutaneous B-cell lymphoma. The typical immunophenotype includes expression of both CD20 and BCL6, with the majority of cases lacking expression of CD10, BCL2, and the characteristic t(14;18)/IGH-BCL2 rearrangement seen in systemic follicular lymphoma (FL). Plasmacytic differentiation (PD) is an uncommon finding in both systemic and cutaneous FLs and presents a diagnostic challenge when present, leading to the potential for misdiagnosis as marginal zone lymphoma (MZL). Limited reports have described light chain restriction in the plasma cell component of FLs with PD, and rare cases of PCFCL with PD have been described. While the IGH-BCL2 translocation has been identified in a subset of FLs with PD, the presence of the BCL2 translocation in monotypic plasma cells of PCFCL has not been previously described to our knowledge. Here, we report a case of PCFCL with extensive PD in a 77-year-old woman that was favored to represent primary cutaneous MZL on an initial punch biopsy. Excisional biopsy, however, revealed that the atypical lymphocytes expressed CD10, BCL6, and BCL2, while the plasma cell component demonstrated light-chain lambda restriction. FISH studies showed the presence of an IGH-BCL2 translocation in both the lymphocytic and plasmacytic components.

Germinal Center Cells Turning to the Dark Side: Neoplasms of B Cells, Follicular Helper T Cells, and Follicular Dendritic Cells

Gaining knowledge of the neoplastic side of the three main cells—B cells, Follicular Helper T (Tfh) cells, and follicular dendritic cells (FDCs) —involved in the germinal center (GC) reaction can shed light toward further understanding the microuniverse that is the GC, opening the possibility of better treatments. This paper gives a review of the more complex underlying mechanisms involved in the malignant transformations that take place in the GC. Whilst our understanding of the biology of the GC-related B cell lymphomas has increased—this is not reviewed in detail here—the dark side involving neoplasms of Tfh cells and FDCs are poorly studied, in great part, due to their low incidence. The aggressive behavior of Tfh lymphomas and the metastatic potential of FDCs sarcomas make them clinically relevant, merit further attention and are the main focus of this review. Tfh cells and FDCs malignancies can often be misdiagnosed. The better understanding of these entities linked to their molecular and genetic characterization will lead to prediction of high-risk patients, better diagnosis, prognosis, and treatments based on molecular profiles.

Grade I, II and III Follicular Lymphomas Express Ig VH Genes with Different Patterns of Somatic Mutation

Follicular lymphoma (FL) is an indolent, B-cell, non-Hodgkin’s lymphoma with varying cytological appearance and clinical behavior. The genetic hallmark of FL is the t(14;18) translocation, and as a germinal center derived entity it is also characterized by somatic hypermutation of the immunoglobulin heavy chain (IgH) gene. In an attempt to correlate this molecular signature with the cytological grading of FL, we have analyzed the IgH variable (IgV_H), regions in all cytological grades of FL. Four FL cases showing t(14;18) translocation were classified into grade I-III categories according to the current WHO guidelines. The IgV_H gene segments were PCR-amplified, sequenced, and compared to their respective germline IgV_H sequences. The neoplastic cells of grade I and II FLs revealed clonally related, but highly divergent IgV_H gene sequences indicating the ongoing nature of somatic hypermutation. Grade III FL also showed extensive presence of somatic hypermutation, but these mutations were not associated with intraclonal divergence. Thus, these results suggest that grade I-II and grade III FL may represent different biological entities. The presence of ongoing somatic hypermutation of IgV_H sequences in grade I and II FLs is compatible with direct follicular origin of these tumor cells, contrasting the homogenous, stable clones of grade III FL resembling a post-follicular stage of B-cell development. Our findings demonstrate that contrary to the three tiered cytological grading, molecular features of IgH genes classify FL into two distinct subcategories. These studies also suggest that with progression FL gains post-follicular–like molecular features and becomes independent of the germinal center microenvironment.

Diffuse large B-cell lymphoma variants: an update

Diffuse large B-cell lymphoma (DLBCL) is the most common type of lymphoma, representing approximately one-third of all cases worldwide. In the World Health Organization (WHO) classification of lymphomas, most cases of DLBCL are designated as not otherwise specified (NOS). About 20% of cases, however, are designated as specific variants of DLBCL. These variants, 13 in total, are specified on the basis of distinctive morphological or immunophenotypic findings or distinctive biological or clinical issues associated with their diagnoses. In this review we discuss the following variants: T-cell/histiocyte-rich large B-cell lymphoma; ALK-positive large B-cell lymphoma; plasmablastic lymphoma; intravascular large B-cell lymphoma; large B-cell lymphoma with IRF4 rearrangement; primary mediastinal large B-cell lymphoma; primary cutaneous diffuse large B-cell lymphoma, leg type; primary diffuse large B-cell lymphoma of the central nervous system; diffuse large B-cell lymphoma associated with chronic inflammation; lymphomatoid granulomatosis; primary effusion lymphoma; and HHV8-positive diffuse large B-cell lymphoma, NOS. Two additional variants recognised in the WHO classification, EBV-positive diffuse large B-cell lymphoma and EBV-positive mucocutaneous ulcer are discussed elsewhere in another review within this issue of Pathology. Although not recognised as a specific variant in the current WHO classification, primary testicular diffuse large B-cell lymphoma also has unique biological features and requires some modification of the standard treatment approach for patients with DLBCL. Therefore, we suggest that primary testicular diffuse large B-cell lymphoma also should be recognised as a specific variant of DLBCL in a future version of the WHO classification.