Cyclin D1-negative Blastoid Mantle Cell Lymphoma Identified by SOX11 Expression

Primary large B-cell lymphoma of the central nervous system: A reappraisal of CD5-positive cases based on clinical, pathological, and molecular evaluation

CD5 expression is seen in 5%-10% of de novo diffuse large B-cell lymphomas (DLBCLs). Primary large B-cell lymphoma of the central nervous system (PCNS-LBCL) also exhibits CD5 expression in a minority of cases, however, clinicopathological and molecular features remain largely unclarified. Here we present the clinical, molecular, and pathological features of 11 CD5-positive (+) PCNS-LBCL cases, occupying 6.7% of all 165 PCNS-LBCLs diagnosed in our institutions. While CD5+ systemic DLBCL has been recognized as a distinctive subgroup showing an aggressive clinical course, no obvious differences were found between CD5+ and CD5-negative subgroups among the present CNS patients clinically. MYD88 p.L265P and CD79B p.Y196 mutations were detected in eight (73%) and seven (64%) cases, respectively, supporting previous reports. Notably, the microenvironmental immune cells were universally PD-L1/CD274-positive, and the higher levels tended to present favorable overall survival, as already evidenced in the PCNS-LBCL series. In contrast, neoplastic PD-L1/CD274 expression was undetectable in all cases. Indeed, no structural variations or copy number alterations involving PD-1 ligands were detected by targeted-capture sequencing and fluorescence in situ hybridization. While further studies are warranted, we may have confirmed similarity between PCNS-LBCLs and intravascular large B-cell lymphomas from a molecular standpoint.

Identification of CD5/SOX11 double-negative pleomorphic mantle cell lymphoma

Cyclin D1 protein-positive diffuse large B cell lymphoma (DLBCL) has an immunophenotype of CD5(-) cyclin D1(+) SOX11(-), and most cases lack a CCND1 rearrangement and have a gene expression profile of DLBCL. Rarely, cyclin D1 protein-positive DLBCL harbors a CCND1 rearrangement, and some genetic copy number features typical of mantle cell lymphoma (MCL) have been detected. Since gene expression studies have not been performed, whether such CCND1-rearranged cases represent cyclin D1 protein-positive DLBCL or CD5/SOX11 double-negative pleomorphic MCL remains unclear. To date, no cases of CD5/SOX11 double-negative MCL have been reported. In this study, we collected eight cases initially diagnosed as cyclin D1 protein-positive DLBCL, including four with a CCND1 rearrangement and four without. Immunohistochemically, all four CCND1-rearranged cases had >50% of tumor cells positive for cyclin D1 protein, whereas only one (25%) non-rearranged case had >50% positive tumor cells. Analysis of genome-wide copy number, mutational, and gene expression profiles revealed that CCND1-rearranged cases were similar to MCL, whereas CCND1-non-rearranged cases resembled DLBCL. Despite the SOX11 negativity by immunohistochemistry, CCND1-rearranged cases had a notable trend (P = 0.064) of higher SOX11 mRNA levels compared to non-rearranged cases. Here, we show for the first time that CCND1 rearrangement could be useful for identifying CD5/SOX11 double-negative pleomorphic MCL in cases diagnosed as cyclin D1 protein-positive DLBCL. Cases with >50% cyclin D1 protein-positive tumor cells immunohistochemically and higher SOX11 mRNA levels are more likely to have a CCND1 rearrangement, and fluorescence in situ hybridization can be used to detect the rearrangement.

SOX11+ Large B-Cell Neoplasms: Cyclin D1-Negative Blastoid/Pleomorphic Mantle Cell Lymphoma or Large B-Cell Lymphoma?

Large or blastoid B-cell neoplasms that are SOX11+ are a diagnostic dilemma and raise a differential diagnosis of cyclin D1-negative blastoid/pleomorphic mantle cell lymphoma (MCL) versus diffuse large B-cell lymphoma (DLBCL) or blastoid high-grade B-cell lymphoma (HGBL) with aberrant SOX11 expression. Here we report a study cohort of 13 SOX11+ large/blastoid B-cell neoplasms. Fluorescence in situ hybridization analysis was negative for CCND1 rearrangement in all 13 cases; 1 of 8 (12.5%) cases tested showed CCND2 rearrangement and 2 (25%) cases had extracopies of CCND2. Gene expression profiling showed that the study group had a gene expression signature similar to cyclin D1+ blastoid/pleomorphic MCL but different from DLBCL. Principal component analysis revealed that the cohort cases overlapped with cyclin D1+ blastoid/pleomorphic MCL but had minimal overlap with DLBCL. All patients in the cohort had clinicopathologic features similar to those reported for patients with cyclin D1+ MCL. We also performed a survey of SOX11 expression in a group of 85 cases of DLBCL and 24 cases of blastoid HGBL. SOX11 expression showed a 100% specificity and positive predictive value for the diagnosis of MCL. Overall, the results support the conclusion that large or blastoid B-cell neoplasms that are positive for SOX11 are best classified as cyclin D1-negative blastoid/pleomorphic MCL, and not as DLBCL or blastoid HGBL. We also conclude that SOX11 is a specific marker for the diagnosis of MCL, including cyclin D1-negative blastoid/pleomorphic MCL cases and should be performed routinely on blastoid/large B-cell neoplasms to help identify potential cases of cyclin D1-negative blastoid/pleomorphic MCL.

Aggressive B-cell non-Hodgkin lymphomas: a report of the lymphoma workshop of the 20th meeting of the European Association for Haematopathology

Aggressive B-cell non-Hodgkin lymphomas are a heterogeneous group of diseases and our concepts are evolving as we learn more about their clinical, pathologic, molecular genetic features. Session IV of the 2020 EAHP Workshop covered aggressive, predominantly high-grade B-cell lymphomas, many that were difficult to classify. In this manuscript, we summarize the features of the submitted cases and highlight differential diagnostic difficulties. We specifically review issues related to high-grade B-cell lymphomas (HGBCLs) with MYC and BCL2 and/or BCL6 rearrangements including TdT expression in these cases, HGBCL, not otherwise specified, large B-cell lymphomas with IRF4 rearrangement, high-grade/large B-cell lymphomas with 11q aberration, Burkitt lymphoma, and pleomorphic mantle cell lymphoma. Since the workshop, the 5th edition of the WHO Classification for Haematolymphoid Tumours (WHO-HAEM5) and International Consensus Classification (ICC) 2022 were published. We endeavor to use the updated terminology.

Cyclin-D1 positive B cell lymphoma with intravascular and interstitial involvement of kidney and bone marrow

Kidney involvement is rare in non-Hodgkin's lymphomas (NHL), and can be caused by direct lymphoid infiltration, paraneoplastic glomerulonephritis (GN), or both. Herein, we present a case of acute kidney injury (AKI) due to renal cyclin-D1 positive B cell lymphoma infiltration. To our knowledge, this is the first case where a renal biopsy revealed intravascular neoplastic cells along with parenchymal infiltration.

Deep Learning-Based Nuclear Morphometry Reveals an Independent Prognostic Factor in Mantle Cell Lymphoma

Blastoid/pleomorphic morphology is associated with short survival in mantle cell lymphoma (MCL), but its prognostic value is overridden by Ki-67 in multivariate analysis. Herein, a nuclear segmentation model was developed using deep learning, and nuclei of tumor cells in 103 MCL cases were automatically delineated. Eight nuclear morphometric attributes were extracted from each nucleus. The mean, variance, skewness, and kurtosis of each attribute were calculated for each case, resulting in 32 morphometric parameters. Compared with those in classic MCL, 17 morphometric parameters were significantly different in blastoid/pleomorphic MCL. Using univariate analysis, 16 morphometric parameters (including 14 significantly different between classic and blastoid/pleomorphic MCL) emerged as significant prognostic factors. Using multivariate analysis, Biologic MCL International Prognostic Index (bMIPI) risk group (P = 0.025), low skewness of nuclear irregularity (P = 0.020), and high mean of nuclear irregularity (P = 0.047) emerged as independent adverse prognostic factors. Additionally, a morphometric score calculated from the skewness and mean of nuclear irregularity (P = 0.0038) was an independent prognostic factor in addition to bMIPI risk group (P = 0.025), and a summed morphometric bMIPI score was useful for risk stratification of patients with MCL (P = 0.000001). These results demonstrate, for the first time, that a nuclear morphometric score is an independent prognostic factor in MCL. It is more robust than blastoid/pleomorphic morphology and can be objectively measured.

How to Diagnose and Treat CD5-Positive Lymphomas Involving the Spleen

Patients with CD5-expressing lymphomas presenting with splenomegaly are frequently diagnosed with chronic lymphocytic leukemia. The most important differential diagnosis is mantle cell lymphoma, both in its classical and leukemic, non-nodal forms, given its prognostic and therapeutic implications. Other small B-cell neoplasms that frequently involve the spleen and occasionally express CD5 include the splenic marginal zone lymphoma, hairy cell leukemia and, rarely, lymphoplasmacytic lymphoma. The frequency of CD5 positivity depends in part on the sensitivity of the detection methods employed. Usually, a combination of morphological, immunophenotypic and molecular findings allows for a precise sub-classification of CD5-positive, low-grade B-cell lymphomas of the spleen. Some of these tumors may display a mixture of small and larger B cells, raising the possibility of more aggressive lymphomas, such as diffuse large B-cell lymphomas (DLBCL). Approximately 5-10% of DLBCL are CD5-positive and some may manifest as primary splenic lesions. When available, the morphology of DLBCL in the splenic tissue is distinctive and a leukemic picture is very rare. In conclusion, the appropriate morphological and clinical context assisted by flow cytometry panels and/or immunohistochemistry allows the differential diagnosis of CD5-positive, non-Hodgkin, B-cell lymphomas involving the spleen.

SOX11 Inhibitors Are Cytotoxic in Mantle Cell Lymphoma

PURPOSE

Mantle cell lymphoma (MCL) is a fatal subtype of non-Hodgkin lymphoma. SOX11 transcription factor is overexpressed in the majority of nodal MCL. We have previously reported that B cell-specific overexpression of SOX11 promotes MCL pathogenesis via critically increasing BCR signaling in vivo. SOX11 is an attractive target for MCL therapy; however, no small-molecule inhibitor of SOX11 has been identified to date. Although transcription factors are generally considered undruggable, the ability of SOX11 to bind to the minor groove of DNA led us to hypothesize that there may exist cavities at the protein-DNA interface that are amenable to targeting by small molecules.

EXPERIMENTAL DESIGN

Using a combination of in silico predictions and experimental validations, we report here the discovery of three structurally related compounds (SOX11i) that bind SOX11, perturb its interaction with DNA, and effect SOX11-specific anti-MCL cytotoxicity.

RESULTS

We find mechanistic validation of on-target activity of these SOX11i in the inhibition of BCR signaling and the transcriptional modulation of SOX11 target genes, specifically, in SOX11-expressing MCL cells. One of the three SOX11i exhibits relatively superior in vitro activity and displays cytotoxic synergy with ibrutinib in SOX11-expressing MCL cells. Importantly, this SOX11i induces cytotoxicity specifically in SOX11-positive ibrutinib-resistant MCL patient samples and inhibits Bruton tyrosine kinase phosphorylation in a xenograft mouse model derived from one of these subjects.

CONCLUSIONS

Taken together, our results provide a foundation for therapeutically targeting SOX11 in MCL by a novel class of small molecules.

Cutaneous Involvement by Mantle Cell Lymphoma: Expanding the Spectrum of Histopathologic Findings in a Series of 9 Cases

Mantle cell lymphoma (MCL) is an aggressive B-cell neoplasm with cutaneous involvement in ∼1% of cases. We present a single institutional series of nine patients (12 specimens) with cutaneous involvement by systemic MCL and review the clinicopathologic features. Six males and 3 females (age range 55-87 years) were included. Sites of involvement were head and neck (n = 3), trunk (n = 5), and extremities (n = 4). Histopathologically, 3 showed classic cytomorphology, 2 were blastoid, 3 pleomorphic, and 1 showed features resembling marginal zone lymphoma. Two cases presented with cutaneous lesions as the first tissue manifestation of the disease. A second malignancy was identified in 3/9 cases (2 melanomas and 1 papillary thyroid carcinoma). In one patient, MCL was juxtaposed with metastatic melanoma within the same biopsy specimen. Fluorescence in situ hybridization studies, when available, demonstrated the characteristic t(11,14) translocation. Direct immunofluorescence was performed on one case and showed immunoglobulin M (IgM) expression on the tumor cells. Follow-up was available in 7 cases (mean 42 months, range 6-78 months) and revealed death from disease for 6 patients that occurred within 1 week to 11 months (mean 4 months) after cutaneous involvement. In our series, 6/9 cases demonstrated blastoid, pleomorphic, or marginal zone lymphoma-like morphologies that could potentially mimic other hematolymphoid neoplasms. MCL may show surface IgM expression on DIF or may occur in association with other solid tumors. Immunohistochemistry for cyclin D1 and/or SOX-11 may be helpful for diagnosis, and imaging studies may be necessary to detect systemic involvement when cutaneous involvement is the first manifestation of the disease.

Aggressive Cyclin D1 Negative Blastoid Variant Mantle Cell Lymphoma-A Case Report

A 68-year-old male presents with generalized lymphadenopathy and fever of short duration. Axillary lymph node excision was performed and was sent for histopathological evaluation. Microscopic evaluation of the submitted lymph node revealed diffuse proliferation of intermediate-sized atypical lymphoid cells with round nuclei, irregular membranes, finely dispersed chromatin, and inconspicuous nucleoli. Mitotic figures were frequently seen. Immunohistochemical evaluation revealed diffuse expression of CD20, CD5, CD10, B-cell lymphoma 2 (Bcl2), and B-cell lymphoma 6 (Bcl6). Atypical lymphoid cells were negative for cyclin D1; however, showed diffuse and strong nuclear expression of SOX11. MIB1 proliferation index was high (Ki67: 90%-95%). Based on morphological features and immunohistochemical findings a diagnosis of "cyclin D1 negative aggressive blastoid variant of mantle cell lymphoma (MCL)" was offered. The classic morphology of MCL is seen in 90% of cases, while the remaining (∼10%) are considered as variants. A blastoid variant is an aggressive subtype that can lack expression of CD5 as well as cyclin D1, but instead expresses CD10, Bcl6, and CD23. SOX11 expression is seen in 90% cases of MCL and in almost 100% cases of cyclin D1 negative MCL. The current case highlights the unusual morphologic and aggressive variant of MCL and a significant role of SOX11 in its diagnosis.

CD5-negative blastoid variant mantle cell lymphoma: a diagnostic dilemma

We encountered two cases of CD5^- blastoid variant mantle cell lymphoma (MCL), prompting us to investigate the proportion of CD5 negativity in MCL and assess the diagnosis of aggressive MCL variants. Among 117 patients diagnosed with MCL, CD5 negativity was observed in 13% (13/104) of cases with classical MCL and 15% (2/13) of cases with blastoid/pleomorphic variant MCL. Of the aggressive MCL variant cases, tumor cells exhibited intermediate nuclear size and required differential diagnosis between blastoid variant and classical MCL in six patients, and classical MCL cells were found in the background of aggressive variant tumors or in other sites in six patients. Of 1534 patients with diffuse large B-cell lymphoma (DLBCL), CD5 positivity was observed in 8% (121/1534) of cases. Immunohistochemical staining for cyclin D1 performed for these cases revealed one cyclin D1-positive and IGH/CCND1 fusion-positive case (0.9%, 1/114), namely pleomorphic variant MCL. Of the remaining 1413 patients initially diagnosed with CD5^- DLBCL, the diagnoses of two patients (0.1%) were amended to CD5^- blastoid variant MCL in the relapse phase based on morphology, cyclin D1 immunostaining, and fluorescence in situ hybridization. The incidence of CD5 negativity was similar between classical MCL and two aggressive variants. Accurate diagnosis of MCL variants was enabled by identifying a classical MCL component and/or CD5 positivity; however, we misdiagnosed two cases of CD5^- blastoid variant MCL. A small number of MCL variants may be included in CD5^- DLBCL cases. The diagnosis of CD5^- aggressive variant MCL remains challenging but crucial because of its therapeutic significance.

Complexities in the diagnosis of large B-cell lymphomas, classic Hodgkin lymphomas and overlapping peripheral T-cell lymphomas simplified: An evidence-based guide

The diagnosis of a large B-cell lymphoma and classic Hodgkin lymphoma (CHL) is often straightforward. However, in select circumstances, these simple diagnoses can be quite complex. In part, diagnostic difficulty may be due to uncertainty in the evaluation of morphologic and immunophenotypic features along a biologic continuum, or alternatively arise from uncertainty in predicting the behavior and outcomes of patients. Here, we systematically discuss and review areas of diagnostic difficulty in the diagnosis of large B-cell lymphomas (LBCL), classic Hodgkin lymphomas (CHL) and peripheral T-cell lymphomas (PTCL). We provide careful data-driven analyses and evidence-based approaches to help guide pathologists and clinicians. We discuss: 1) marginal zone lymphomas with increased large cells versus diffuse large B-cell lymphoma (DLBCL), 2) chronic lymphocytic leukemia with expanded proliferation centers versus diffuse large B-cell lymphoma (DLBCL), 3) chronic lymphocytic leukemia with Hodgkin/Reed-Sternberg-like cells versus CHL arising from chronic lymphocytic leukemia, 4) complex cases of follicular lymphoma versus DLBCL, 5) PTCL with large B-cell proliferations versus PTCL with LBCL, 6) PTCL with Hodgkin/Reed-Sternberg-like cells versus CHL, and finally 7) blastoid/pleomorphic mantle cell lymphoma versus DLBCL. Our evidence and data driven approach may serve as a useful diagnostic guide.

A Practical Approach to Diagnosis of B-Cell Lymphomas With Diffuse Large Cell Morphology

CONTEXT.—

Large B-cell lymphomas represent the most common non-Hodgkin lymphomas and often present as extranodal masses with advanced stage similar to metastatic tumors. Without proper intraoperative, microscopic, immunophenotypic, and cytogenetic evaluation they may be mistaken for other hematopoietic or even nonhematopoietic tumors. Also, diffuse large B-cell lymphomas often have clinical, morphologic, immunophenotypic, and cytogenetic clinical features that are similar to those of other less common B-cell lymphomas. Furthermore, classification of these neoplasms is continually becoming more refined.

OBJECTIVE.—

To provide a rational, methodic approach to the evaluation of large B-cell lymphomas for community practice pathologists who provide general pathology services.

DATA SOURCES.—

This review incorporates guidelines detailed in the 2017 update to the World Health Organization's Classification of Tumours of Haematopoietic and Lymphoid Tissues in addition to other recent peer-reviewed publications.

CONCLUSIONS.—

Many large B-cell neoplasms respond favorably to current treatments, but these cases also require accurate and timely diagnoses. We propose a process following a brief checklist that focuses on diffuse large B-cell lymphoma, the most common entity, and rules out other similar lymphomas in a stepwise fashion.

Clinicopathological features and prognostic value of SOX11 in childhood acute lymphoblastic leukemia

Acute lymphoblastic leukemia is marked by aberrant transcriptional features that alter cell differentiation, self-renewal, and proliferative features. We sought to identify the transcription factors exhibiting altered and subtype-specific expression patterns in B-ALL and report here that SOX11, a developmental and neuronal transcription factor, is aberrantly expressed in the ETV6-RUNX1 and TCF3-PBX1 subtypes of acute B-cell leukemias. We show that a high expression of SOX11 leads to alterations of gene expression that are typically associated with cell adhesion, migration, and differentiation. A high expression is associated with DNA hypomethylation at the SOX11 locus and a favorable outcome. The results indicate that SOX11 expression marks a group of patients with good outcomes and thereby prompts further study of its use as a biomarker.

Diagnostic accuracy of SOX11 immunohistochemistry in mantle cell lymphoma: A meta-analysis

SOX11 is a transcription factor that is normally expressed in the fetal brain and has also been detected in some malignant tumors, including mantle cell lymphoma (MCL). MCL is a mature B-cell lymphoma that characteristically expresses cyclin D1, which has been used as a diagnostic tumor marker. SOX11 has also recently emerged as a tumor marker for MCL, particularly in cyclin D1-negative MCLs and to distinguish between MCLs and other cyclin D1-positive lymphomas. In this study, we evaluated the diagnostic accuracy of SOX11 immunohistochemistry for the diagnosis of MCL using a meta-analysis. A comprehensive literature search was performed using the PubMED, EMBASE, and Cochrane library through May 9, 2018. In total, 14 studies were included in our meta-analysis. The sensitivity, specificity, and area under the curve calculated from the summary receiver operator characteristic were 0.9, 0.95, and 0.934, respectively. Effect sizes of log positive likelihood ratios, log negative likelihood ratios, and log diagnostic odds ratios were 2.67, -2.12, and 5.27, respectively. Statistically significant substantial heterogeneity was observed for specificity (I2 = 95%), but not for sensitivity. Subgroup analysis and meta-regression were performed to explain the heterogeneity in specificity and showed that the proportions of Burkitt's lymphoma, lymphoblastic lymphoma, and hairy cell leukemia were significant covariates among studies using rabbit polyclonal antibodies. Overall, this meta-analysis showed that SOX11 was a useful diagnostic marker for MCL, with the clone MRQ-58 mouse monoclonal antibody showing particularly robust performance.

SOX11, a key oncogenic factor in mantle cell lymphoma

PURPOSE OF REVIEW

SOX11 has emerged as a key transcription factor in the pathogenesis of mantle cell lymphoma (MCL) whereas it is not expressed in normal B cells or virtually in any other mature B-cell neoplasm. This review will examine the role of SOX11 as a biomarker in MCL, the new information on its transcriptional targets, and the mechanisms regulating its expression in MCL.

RECENT FINDINGS

SOX11 is highly expressed in conventional MCL, including cyclin D1-negative cases, but it is not expressed in the indolent leukemic nonnodal MCL subtype. These two MCL subtypes also differ in their cell-of-origin, IGHV mutational status and genomic instability. SOX11 promotes tumor growth of MCL cells in vivo and regulates a broad transcriptional program that includes B-cell differentiation pathways and tumor-microenvironment interactions, among others. The mechanisms upregulating SOX11 in MCL are not well understood but are mediated in part by the three-dimensional reconfiguration of the DNA, bringing together a distant enhancer region and the SOX11 promoter.

SUMMARY

SOX11 is a relevant element in the pathogenesis of MCL and has been instrumental to identify two distinct clinicobiological subtypes of this tumor. Further studies should clarify the mechanisms mediating its oncogenic potential and leading to its intriguing expression in these tumors.

SOX11 augments BCR signaling to drive MCL-like tumor development

Mantle cell lymphoma (MCL) is characterized by increased B-cell receptor (BCR) signaling, and BTK inhibition is an effective therapeutic intervention in MCL patients. The mechanisms leading to increased BCR signaling in MCL are poorly understood, as mutations in upstream regulators of BCR signaling such as CD79A, commonly observed in other lymphomas, are rare in MCL. The transcription factor SOX11 is overexpressed in the majority (78% to 93%) of MCL patients and is considered an MCL-specific oncogene. So far, attempts to understand SOX11 function in vivo have been hampered by the lack of appropriate animal models, because germline deletion of SOX11 is embryonically lethal. We have developed a transgenic mouse model (Eμ-SOX11-EGFP) in the C57BL/6 background expressing murine SOX11 and EGFP under the control of a B-cell-specific IgH-Eμ enhancer. The overexpression of SOX11 exclusively in B cells exhibits oligoclonal B-cell hyperplasia in the spleen, bone marrow, and peripheral blood, with an immunophenotype (CD5⁺CD19⁺CD23^-) identical to human MCL. Furthermore, phosphocytometric time-of-flight analysis of the splenocytes from these mice shows hyperactivation of pBTK and other molecules in the BCR signaling pathway, and serial bone marrow transplant from transgenic donors produces lethality with decreasing latency. We report here that overexpression of SOX11 in B cells promotes BCR signaling and a disease phenotype that mimics human MCL.

Long non-coding RNA profile in mantle cell lymphoma identifies a functional lncRNA ROR1-AS1 associated with EZH2/PRC2 complex

Mantle cell lymphoma (MCL) is an aggressive B-cell lymphoma characterized by rapid disease progression. The needs for new therapeutic strategies for MCL patients call for further understanding on the molecular mechanisms of pathogenesis of MCL. Recently, long noncoding RNAs (lncRNAs) have been recognized as key regulators of gene expression and disease development, however, the role of lncRNAs in non-Hodgkin lymphoma and specifically in MCL is still unknown. Next generation RNA-sequencing was carried out on MCL patient samples along with normal controls and data was analyzed. As a result, several novel lncRNAs were found significantly overexpressed in the MCL samples with lncRNA ROR1-AS1 the most significant one. We cloned the ROR1-AS1 lncRNA in expression vector and ectopically transfected in MCL cell lines. Results showed that overexpression of ROR1-AS1 lncRNA promoted growth of MCL cells while decreased sensitivity to the treatment with drugs ibrutinib and dexamethasone. ROR-AS1 overexpression also decreased the mRNA expression of P16 (P = 0.21), and SOX11 (p = 0.017), without much effect on P53, ATM and P14 mRNA. RNA-immunoprecipitation assays demonstrated high affinity binding of lncRNA ROR1-AS1 with EZH2 and SUZ12 proteins of the polycomb repressive complex-2 (PRC2). Suppressing EZH2 activity with pharmacological inhibitor GSK343 abolished binding of ROR1-AS1 with EZH2. Taken together, this study identified a functional lncRNA ROR-AS1 involved with regulation of gene transcription via associating with PRC2 complex, and may serve as a novel biomarker in MCL patients.

Cutaneous mantle cell lymphoma: a clinicopathologic review of 10 cases

Cutaneous mantle cell lymphoma (MCL) is exceedingly rare, almost always occurring as a dissemination of systemic MCL. To date, only 32 cases have been described. We report a series of 10 cases of MCL in the skin, and provide a comprehensive clinicopathologic review with clinical follow-up. Our cases occurred in older individuals (mean age = 70) and were more frequently in men (90%). Half of them presented in the head and neck region as a mass/nodule, and the remainder in the trunk and extremities as nodules. All patients have stage IV disease. In two of the 10 cases (20%) the cutaneous lesions preceded the diagnosis of disseminated disease. In two of the seven cases with available clinical follow-up information (33%) the skin was immediately involved after the diagnosis of MCL, and in three of the seven the skin was the first site of recurrence (mean interval = 57 months). The mean time to recurrence of the disease was 45.4 months and the overall survival was 66.3 months. Histologically six out of 10 cases (60%) had either pleomorphic or blastoid morphology (four out of 10 and two out of 10, respectively). The mean number of mitoses per 10 high-power fields was 18.44. While nine out of 10 cases expressed cyclin-D1, one case was not positive for cyclin-D1 but did label with SOX-11. Limited cytogenetic data showed trisomy 14 in one case, in addition to the t(11;14) translocation.

Diagnostic utility of SOX11 immunohistochemistry in differentiating cutaneous spread of mantle cell lymphoma from primary cutaneous B-cell lymphomas

BACKGROUND

Mantle cell lymphoma (MCL) is associated with the worst prognosis among low-grade B-cell lymphomas. While cutaneous involvement by nodal or systemic MCL is uncommon, its differentiation from primary cutaneous B-cell lymphoma (CBCL) or cutaneous involvement by other extra-cutaneous BCL is challenging as neither histomorphology nor immunophenotype can be absolutely specific. We analyzed the diagnostic utility of SOX11 immunohistochemistry in differentiating secondary cutaneous MCL from other low-grade CBCL.

METHODS

Immunohistochemical staining with anti-SOX11 antibody was performed on 8 cases of secondary cutaneous MCL, 16 secondary cutaneous CLL, 20 primary cutaneous MZL, 12 cutaneous FCL (6 primary, 6 secondary), 7 primary cutaneous DLBCL, leg type, 5 systemic DLBCL and 3 B-ALL. SOX11 and cyclin D1 staining were compared in secondary cutaneous MCL.

RESULTS

Nuclear SOX11 staining was seen in seven of eight cases (88%) of secondary cutaneous MCL, including a case with minimal cyclin D1 expression. All other CBCL lacked detectable nuclear SOX11 expression. The sensitivity and specificity for SOX11 in MCL were 87.5 and 100%, respectively. Both the sensitivity and specificity for combined SOX11 and cyclin D1 immunohistochemistry were 100%.

CONCLUSION

SOX11 immunohistochemistry could be a useful adjunct in distinguishing secondary cutaneous MCL from other CBCL.

Mantle cell lymphoma: a report of 31 nodal and extranodal fine-needle aspirates

INTRODUCTION

This study reports our experience using aspiration cytopathology coupled with various auxiliary tests in achieving diagnostic accuracy in cases of mantle cell lymphoma (MtCL) from both nodal and extranodal sites.

MATERIALS AND METHODS

Specimens retrieved from our cytology database used search codes for MtCL. Tissue files were searched for any cases of MtCL that had corresponding fine-needle aspiration biopsy (FNAB) cytopathology. FNAB was performed using the standard technique.

RESULTS

Thirty-one aspirates of MtCL were recovered: 11 primary and 20 recurrent examples over a wide age range (x = 63 years). All had histologic confirmation. Nearly one-half were from extranodal sites (14; 45%), mostly representing skin/soft tissue masses. Microscopic examination showed a monotonous proliferation of small-medium lymphocytes in a dispersed pattern with dendritic cells and rarely tingible-body macrophages. Flow cytometry (FCM) performed on all but 6 aspirates demonstrated light chain clonality. In 12 aspirates, ancillary testing in addition to FCM consisted of fluorescence in situ hybridization only (6 cases), fluorescence in situ hybridization plus immunohistochemical (IHC) (2), and IHC only (4). One case had cell block IHC alone without FCM. A specific diagnosis of MtCL was made from 45% of primary and 89% of recurrent MtCL cases. No examples of a correct, specific FNAB diagnosis of MtCL were made without the use of some form of auxiliary testing.

CONCLUSIONS

Aspirates of MtCL are characterized by nonspecific relatively uniform small-sized to medium-sized lymphocytes. A specific diagnosis of MtCL is achievable in nodal/extranodal sites, but only when a combination of auxiliary studies is judiciously employed.

CD5 positivity is an independent adverse prognostic factor in elderly patients with diffuse large B cell lymphoma

Diffuse large B cell lymphoma (DLBCL) is the most common non-Hodgkin lymphoma. Age over 60 years is one of the five parameters of the International Prognostic Index (IPI), which is the most important clinical prognostic predictor in DLBCL. A previous study on German DLBCL patients over 60 years of age showed that immunoblastic morphology, but not germinal center B cell-like (GCB)/non-GCB subtype, correlated with short survival. We collected 174 DLBCL cases over 60 years of age in Taiwan and performed immunophenotyping and detection of Epstein-Barr virus (EBV)-encoded RNA (EBER) by in situ hybridization. Of the cases, 5.2 % were positive for CD5 and 5.7 % positive for EBER. Neither immunoblastic morphology nor GCB/non-GCB subtype correlated with survival. In univariate analysis, adverse prognostic factors included IPI ≥ 3 (P < 0.000001), B symptoms (P = 0.000075), bone marrow/peripheral blood involvement (P = 0.017), EBER positivity (P = 0.0013), and CD5 positivity (P = 0.016). In multivariate analysis, CD5 positivity was the only independent adverse prognostic factor (HR = 3.16; 95 % CI = 1.34-7.47; P = 0.0087) in addition to IPI ≥ 3 (HR = 3.07; 95 % CI = 1.84-5.11; P = 0.000018). Surprisingly, despite an overall 5.2 % incidence of central nervous system (CNS) relapse in our patients, none of the CD5+ cases experienced CNS relapse (P = 1.00). This is in stark contrast to the more frequent CNS relapse in Japanese CD5+ DLBCL patients. EBER positivity was associated with IPI ≥ 3 (P = 0.010), stage III-IV (P = 0.0082), and B symptoms (P = 0.011). In multivariate analysis, EBER positivity was not an independent adverse prognostic factor (P = 0.81), its effect being due likely to accompanying adverse clinical parameters.

Clinicopathologic features of 112 cases with mantle cell lymphoma

Objective

This study aims to explore the clinicopathologic features of 112 patients with mantle cell lymphoma (MCL).

Methods

Data from 112 MCL cases were collected, and immunohistochemical assay was conducted. Fluorescence in situ hybridization (FISH) detected a break in the CCND1 gene. The t-test was used in the statistical analysis.

Results

All tumor cells in the 112 cases expressed B cell-related antigen, including 1 blastoid subtype and 1 polymorphic subtype. Among all cases, 106 expressed CD5 and 104 expressed cyclin D1. A break in the CCND1 gene was not found in 3 cases with CD5-MCL. IgH/CCND1 polyploid was observed in 2 classic cases.

Conclusion

MCL is a type of special immunophenotypic B-cell lymphoma. The prognoses of blastoid and polymorphic subtypes are poor. Special subtypes should be classified during diagnosis.

The role of tumor suppressor gene SOX11 in prostate cancer

SOX genes play an important role in a number of developmental processes. The transcription factor SOX11 is one of the members of the SOX family emerging as important transcriptional regulators. The aim of this study was to investigate the role of SOX11 in prostate cancer (PCa) and its expression pattern and clinical significance. The gene expression of SOX11 in human PCa tissues compared with benign prostate hyperplasia (BPH) tissues was detected using real-time quantitative reverse transcriptase-polymerase chain reaction (QRT-PCR) analysis and immunohositochemistry. SOX11 overexpression cell model was used to examine the role of SOX11 in cell growth and metastasis in vitro. The results showed that the positive rate of SOX11 staining was 16.67 % (10/60) in cases of prostatic carcinoma and 81.67 % (49/60) in cases of BPH, and the difference of SOX11 expression between PCa and BPH was statistically significant (P < 0.001). SOX11 mRNA level was lowly expressed in PCa cell lines compared to RWPE-1. SOX11 overexpression suppresses PCa cell migration and invasion. In conclusion, our findings demonstrate that SOX11 could suppress cell proliferation, migration, and invasion of PCa in vitro.

Rac1 is correlated with aggressiveness and a potential therapeutic target for gastric cancer

Rac1 is a member of the Rho GTPase family. Rac1 activity is critical in regulating cytoskeleton organization and thus, modulates a diverse spectrum of cellular functions in normal and malignant cells. The aims of the present study were to investigate the expression pattern and clinical significance of Rac1, as well as the role of Rac1 in gastric cancer tumorigenesis and metastasis. The expression of Rac1 in human gastric cancer was explored by immunohistochemistry. The correlation of Rac1 expression with the clinicopathological characteristics and the survival of patients were analyzed by Pearson's Chi-square and Kaplan-Meier analyses, respectively. Rac1 overexpression cell model was used to examine in vitro and in vivo effects of Rac1 in cell growth, migration and invasion. Rac1 was highly expressed in gastric cancer tissues and correlated with differentiation, local invasion, lymph node metastasis and Lauren's classification. Rac1 expression in gastric cancer predicted shorter survival. Overexpression of Rac1 in gastric cancer cells dramatically induced Rac1 activation and rendered a more aggressive phenotype such as increased cell growth and migration/invasion in vitro and in vivo. Inhibiting Rac1 activity by specific inhibitor abrogated the effects of Rac1 on the malignant phenotype. Our clinical findings demonstrated that Rac1 was well correlated with aggressiveness and a negative prognostic factor. In addition, our data on experimental cell models supported the fundamental role of Rac1 in gastric cancer. Given its pivotal role in gastric tumorigenesis and progression, Rac1 can serve as a promising therapeutic target for gastric cancer.

Cyclin D1-positive diffuse large B-cell lymphoma with IGH-CCND1 translocation and BCL6 rearrangement: a report of two cases

OBJECTIVES

To demonstrate and confirm the existence of cyclin D1-positive diffuse large B-cell lymphoma (DLBCL) with IGH-CCND1 rearrangement and discuss the rationale of differentiating this entity from blastoid and pleomorphic variants of mantle cell lymphoma (MCL).

METHODS

Two cyclin D1-positive lymphomas with morphologic features of DLBCL and IGH-CCND1 translocations were characterized with respect to clinical features, as well as morphologic, immunophenotypic, cytogenetic, and molecular findings.

RESULTS

The large tumor cells were CD20+, CD5-, CD10-, BCL6+, MUM1+, and cyclin D1+ in both cases. SOX11 was negative. Epstein-Barr virus-encoded RNA in situ hybridization demonstrated diffuse positivity in case 1. BCL6 and IGH-CCND1 rearrangements were identified by fluorescence in situ hybridization in both cases. Specifically, the diagnosis of a relapsed DLBCL with acquisition of IGH-CCND1 was rendered for case 1, molecularly confirmed by the detection of identical monoclonal IGH rearrangements between the initial diagnostic DLBCL and relapse lymphoma.

CONCLUSIONS

Our study demonstrates convincingly that IGH-CCND1 rearrangement leading to cyclin D1 overexpression can occur in DLBCL and pose a potential diagnostic pitfall, requiring thorough knowledge of the clinicopathologic findings to allow accurate discrimination from a blastoid or pleomorphic MCL. The coexistence of IGH-CCND1 and IGH-BCL6 rearrangements suggest that BCL6 and cyclin D1 may cooperate in the pathogenesis of DLBCL.

Pathology of B-cell lymphomas: diagnosis and biomarker discovery

The diagnosis of B-cell non-Hodgkin lymphomas has changed significantly over the past few decades as new immunophenotypic markers, molecular subtype classification schemes, and novel biomarkers have emerged. Meanwhile, there has been an increasing emphasis on individualizing treatment approaches in accordance with a biologic heterogeneity that has been uncovered within many of the individual B-cell lymphoma entities. The application of high-throughput genomic sequencing to B-cell lymphomas has yielded large amounts of valuable information. The data encompass discoveries essential to an understanding of pathogenesis, clonal or tumoral evolution, and identification of biomarkers that may be useful for prognostic or therapeutic considerations. The following review discusses several of the more common, primarily tissuebased B-cell lymphomas, with a focus on pathologic classification and certain phenotypic characteristics or genetic lesions that apply to refinement of diagnosis and therapy.

New Immunohistochemistry for B-Cell Lymphoma and Hodgkin Lymphoma

Context

B-cell non-Hodgkin lymphoma is a heterogeneous group of lymphoproliferative malignancies with different clinical behaviors and treatments. It is important to differentiate individual B-cell lymphoma to apply the best treatment and management. Morphology and immunohistochemistry are the primary tools used for diagnosing lymphoma. There is a characteristic pattern of expression with immunohistochemical antibodies in most well-defined B-cell lymphomas. Some cases of B-cell lymphoma, however, show unusual morphologic and immunophenotypic features. The new and sometimes more specific antibodies have been developed recently, which may further define those lymphomas. Only with use of the antibodies over time does their true nature and specificity become evident.

Objectives

To present new antibodies for B-cell lymphoma that enhance the probability for diagnosis or can act as alternate markers in unusual cases, in which a B-cell lymphoma does not present with characteristic immunohistochemical staining, and to present prognostic markers that allow for better management of patients with specific B-cell lymphomas.

Data Sources

Data were obtained from literature review and figures from slides in personal practice.

Conclusions

The immunohistochemical antibodies presented in this article increase our ability to understand, diagnosis, and manage patients with B-cell lymphoma.

The metastasis suppressor SOX11 is an independent prognostic factor for improved survival in gastric cancer

SOX11 is involved in gastrulation and in malignant diseases. The aim of this study was to investigate the role of SOX11 in gastric cancer and its expression pattern and clinical significance. SOX11 overexpression cell model was used to examine in vitro and in vivo the role of SOX11 in cell growth and metastasis. Cell cycle analysis and Annexin V/PI double staining were used to investigate the effect of SOX11 on cell cycle progression and apoptosis. The expression of SOX11 in human gastric cancer was examined by immunohistochemistry. The correlation of SOX11 expression with clinicopathological characteristics and survival of patients was analyzed by Pearson’s χ² and Kaplan-Meier analyses, respectively. Cox’s proportional hazard model was employed in multivariate analysis. SOX11 overexpression did not inhibit cell growth but strongly suppressed cell migration/invasion in vitro and in vivo. We found a significant correlation between high SOX11 protein levels and Lauren’s classification (intestinal type), differentiation status (high and medium), and early TNM stage. SOX11 is an independent prognostic factor for improved survival in gastric cancer patients. SOX11 was a potential tumor-suppressor and an independent positive prognostic factor in gastric cancer patients with less advanced clinicopathological features.

Pathology consultation on intermediate-to-large B-cell lymphomas

OBJECTIVES

Intermediate-to-large B-cell lymphomas represent a heterogeneous group of aggressive lesions frequently encountered in practice. The differential diagnosis includes the most common of all lymphomas, diffuse large B-cell lymphoma (DLBCL), as well as Burkitt lymphoma (BL), B-lymphoblastic lymphoma, and the blastoid variant of mantle cell lymphoma. In recent decades, gene expression profiling studies have clarified the biologic origins and features of these diseases. Moreover, clinically relevant subtypes of DLBCL have been identified, and a new category was defined: B-cell lymphoma, unclassifiable, with features intermediate between DLBCL and BL. Herein, we review the salient diagnostic features of the various entities within this differential diagnosis and provide a stepwise diagnostic approach for dealing with challenging cases.

METHODS

A case-based approach is used to highlight diagnostic dilemmas and clinical decision points within the differential diagnosis of intermediate-to-large B-cell lymphomas.

RESULTS

Based on the published literature and World Health Organization criteria, we suggest a diagnostic algorithm for appropriate classification of these lymphomas.

CONCLUSIONS

Correct classification of intermediate-to-large B-cell lymphomas is important, because prognosis and therapeutic approach vary for different tumors and tumor subclasses. Understanding both disease-specific criteria and pathologic features that influence clinical behavior within a category is imperative for evaluation of these lymphomas.

Polyclonal antibody targeting SOX11 cannot differentiate mantle cell lymphoma from B-cell non-Hodgkin lymphomas

OBJECTIVES

To determine whether SOX11 is a diagnostic marker of mantle cell lymphoma (MCL).

METHODS

We analyzed SOX11 expression in 349 B-cell non-Hodgkin lymphomas (B-NHLs) via immunohistochemistry.

RESULTS

Nuclear staining of SOX11 was observed in 54 (93.1%) of 58 MCLs. We noticed that SOX11 protein was also expressed on the nuclei in 8 (21.6%) of 37 B-lymphoblastic lymphomas, 45 (32.6%) of 138 diffuse large B-cell lymphomas, 15 (44.1%) of 34 follicular lymphomas, 8 (30.8%) of 26 Burkitt lymphomas, 2 (10.0%) of 20 chronic lymphocytic leukemia/small cell lymphomas, and 3 (18.8%) of 16 marginal zone lymphomas.

CONCLUSIONS

Although the positive rate of SOX11 expression in MCL was significantly higher than other B-NHLs (P < .001), polyclonal antibody targeting SOX11 is not able to identify MCL from B-NHLs because the nuclear staining of SOX11 was widely positive in B-NHLs.

Indolent mantle cell lymphoma

Over the past decade, it has become increasingly clear that mantle cell lymphoma (MCL) is a more heterogeneous disease than originally recognized. Several groups have reported on a subgroup of patients with a less aggressive course than expected resulting in the term "indolent MCL". Unlike the recognized histologic variants, the definition of indolent mantle cell lymphoma is unclear, and patients with indolent MCL are often identified only after having undergone prolonged periods of observation. In this review, we will discuss clinical and biologic features and provide a framework for the approach in identifying patients with indolent MCL.

Lymphomas of the Gastrointestinal Tract: An Update

The gastrointestinal tract is the most common extranodal site of non-Hodgkin lymphoma. Certain lymphomas have a predilection for the gastrointestinal tract, including extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue, mantle cell lymphoma, natural killer/T-cell lymphoma, and enteropathy-associated T-cell lymphoma. Follicular lymphoma may also be primary to the gastrointestinal tract. In addition to diagnosing neoplastic conditions, it is important to differentiate lymphomas from atypical reactive proliferations. Recent research relevant to non-Hodgkin lymphomas involving this location is reviewed with an emphasis on novel and evolving areas of classification.

CCND2 rearrangements are the most frequent genetic events in cyclin D1(-) mantle cell lymphoma

Cyclin D1(-) mantle cell lymphomas (MCLs) are not well characterized, in part because of the difficulties in their recognition. SOX11 has been identified recently as a reliable biomarker of MCL that is also expressed in the cyclin D1(-) variant. We investigated 40 lymphomas with MCL morphology and immunophenotype that were negative for cyclin D1 expression/t(11;14)(q13;q32) but positive for SOX11. These tumors presented clinically with generalized lymphadenopathy, advanced stage, and poor outcome (5-year overall survival, 48%). Chromosomal rearrangements of the CCND2 locus were detected in 55% of the cases, with an IG gene as partner in 18 of 22, in particular with light chains (10 IGK@ and 5 IGL@). No mutations in the phosphorylation motifs of CCND1, CCND2, or CCND3 were detected. The global genomic profile and the high complexity of the 32 cyclin D1(-) SOX11(+) MCL patients analyzed by copy number arrays were similar to the conventional cyclin D1/SOX11 MCL. 17p deletions and high Ki67 expression conferred a significantly worse outcome for the patients. This comprehensive characterization of a large series of cyclin D1(-) MCL patients indicates that these tumors are clinically and biologically similar to the conventional cyclin D1(+) MCL and provides a basis for the proper identification and clinical management of these patients.

Transformation of indolent mantle cell lymphoma to pleomorphic mantle cell lymphoma: case report and review of clinical and morphologic variants

We report a case of indolent mantle cell lymphoma with progression to pleomorphic mantle cell lymphoma 8 years after initial presentation. The first lymph node biopsy showed expanded mantle zones composed of uniformly small B lymphocytes. A cyclin D1 immunohistochemical stain was negative and the patient was observed. Eight years later, the patient developed symptomatic splenomegaly. Microscopic examination of the spleen revealed expanded mantle zones with an increased number of large cells with irregular nuclear contours. Immunohistochemistry for cyclin D1 was positive. A repeat cyclin D1 immunohistochemical staining performed on the initial lymph node biopsy was positive, indicating an inadequate initial study. Immunoglobulin heavy-chain gene rearrangement studies confirmed clonal identity. A revised diagnosis of indolent mantle cell lymphoma with progression to pleomorphic mantle cell lymphoma was rendered. The differential diagnosis of mantle cell lymphoma, including clinical and morphologic variants, is discussed.

Expanded clinical and experimental use of SOX11 - using a monoclonal antibody

BACKGROUND

The transcription factor SOX11 is of diagnostic and prognostic importance in mantle cell lymphoma (MCL) and epithelial ovarian cancer (EOC), respectively. Thus, there is an unmet clinical and experimental need for SOX11-targeting assays with low background, high specificity and robust performance in multiple applications, including immunohistochemistry (IHC-P) and flow cytometry, which until now has been lacking.

METHODS

We have developed SOX11-C1, a monoclonal mouse antibody targeting SOX11, and successfully evaluated its performance in western blots (WB), IHC-P, fluorescence microscopy and flow cytometry.

RESULTS

We confirm the importance of SOX11 as a diagnostic antigen in MCL as 100% of tissue micro array (TMA) cases show bright nuclear staining, using the SOX11-C1 antibody in IHC-P. We also show that previous reports of weak SOX11 immunostaining in a fraction of hairy cell leukemias (HCL) are not confirmed using SOX11-C1, which is consistent with the lack of transcription. Thus, high sensitivity and improved specificity are demonstrated using the monoclonal SOX11-C1 antibody. Furthermore, we show for the first time that flow cytometry can be used to separate SOX11 positive and negative cell lines and primary tumors. Of note, SOX11-C1 shows no nonspecific binding to primary B or T cells in blood and thus, can be used for analysis of B and T cell lymphomas from complex clinical samples. Dilution experiments showed that low frequencies of malignant cells (~1%) are detectable above background using SOX11 as a discriminant antigen in flow cytometry.

CONCLUSIONS

The novel monoclonal SOX11-specific antibody offers high sensitivity and improved specificity in IHC-P based detection of MCL and its expanded use in flow cytometry analysis of blood and tissue samples may allow a convenient approach to early diagnosis and follow-up of MCL patients.