Mutational frequencies of CD79B and MYD88 vary greatly between primary testicular DLBCL and gastrointestinal DLBCL

Primary gastric diffuse large B-cell lymphoma: A multicentre retrospective study

Primary gastric diffuse large B-cell lymphoma (PG-DLBCL) accounts for the majority of extra-nodal DLBCL. Even so, literature is lacking on early, localised presentations. We studied a cohort of patients with stage I disease, diagnosed between 2006 and 2018, from six centres between Australia, Canada and Denmark. Our goal was to characterise outcomes, review treatment and investigate the role of interim positron emission tomography (iPET). Thirty-seven eligible patients were identified. The median duration of follow-up was 42.2 months. All received chemoimmunotherapy with 91.9% (n = 34) given rituximab, cyclophosphamide, doxorubicin, vincristine and prednisolone (R-CHOP). 35.1% (n = 13) underwent consolidative radiotherapy. Eighteen patients were H. pylori positive and 11 had the documentation of H. pylori eradication therapy. The 4-year progression-free survival and overall survival of R-CHOP was 88% (95% CI: 71-95) and 91% (95% CI: 75-97) respectively. All patients who achieved a partial metabolic response or complete metabolic response on iPET went on to achieve complete response at the end of treatment. R-CHOP-based therapy with iPET assessment appears to offer favourable outcomes, with radiotherapy and H. pylori eradication therapy implemented on a case-by-case basis.

Differences in mutational signature of diffuse large B-cell lymphomas according to the primary organ

BACKGROUND

Comprehensive molecular subtyping of diffuse large B-cell lymphoma (DLBCL) through genetic profiling has broadened our understanding of DLBCL biology. In this study, we investigated whether DLBCL, not otherwise specified (NOS) shows differences in mutational patterns depending on the primary organ.

PATIENTS AND METHODS

Panel-based next-generation sequencing was performed on 345 DLBCL from various primary organs, and patterns of mutations according to primary organs were analyzed.

RESULTS

DLBCL showed a characteristic mutational signature in several primary organs. Among them, the mutational pattern of DLBCL in the breast and ileocecal area was particularly different from that of other DLBCL NOS. In breast DLBCL, MYD88L265P (57.1%), CD79B mutation (42.9%), and CDKN2A/B loss (71.4%) were found at high frequencies, which were similar to the mutation patterns of DLBCL of immune-privileged sites compared with DLBCL NOS. DLBCL in the ileocecal area showed a characteristic mutation pattern with the most frequent TP53 mutation (52.6%) and 18q21 gain (42.1%). This was also different from the mutational pattern observed in the stomach or other intestines. In discriminant analysis, DLBCL of the breast and ileocecal area tended to form separate genetic constellations from other DLBCL NOS.

CONCLUSION

DLBCL NOS has a characteristic mutational profile that depends on the primary organ. In particular, the mutational signature of DLBCL in the breast and ileocecal area was heterogeneous compared with that of other DLBCL NOS. Further research is needed to determine whether primary DLBCL in the breast and ileocecal area can be classified as an independent subtype.

Whole-exome sequencing analysis identifies distinct mutational profile and novel prognostic biomarkers in primary gastrointestinal diffuse large B-cell lymphoma

Background

Diffuse large B-cell lymphoma (DLBCL) is the most common aggressive non-Hodgkin lymphoma, and about 10% of DLBCL cases primarily occur in the gastrointestinal tract. Previous reports have revealed that primary gastrointestinal-DLBCL (pGI-DLBCL) harbors different genetic mutations from other nodal or extranodal DLBCL. However, the exonic mutation profile of pGI-DLBCL has not been fully addressed.

Methods

We performed whole-exome sequencing of matched tumor tissues and blood samples from 53 pGI-DLBCL patients. The exonic mutation profiles were screened, and the correlations between genetic mutations and clinicopathological characteristics were analyzed.

Results

A total of 6,588 protein-altering events were found and the five most frequent mutated genes in our pGI-DLBCL cohort were IGLL5 (47%), TP53 (42%), BTG2 (28%), P2RY8 (26%) and PCLO (23%). Compared to the common DLBCL, significantly less or absence of MYD88 (0%), EZH2 (0%), BCL2 (2%) or CD79B (8%) mutations were identified in pGI-DLBCL. The recurrent potential driver genes were mainly enriched in pathways related to signal transduction, infectious disease and immune regulation. In addition, HBV infection had an impact on the mutational signature in pGI-DLBCL, as positive HBsAg was significantly associated with the TP53 and LRP1B mutations, two established tumor suppressor genes in many human cancers. Moreover, IGLL5 and LRP1B mutations were significantly correlated with patient overall survival and could serve as two novel prognostic biomarkers in pGI-DLBCL.

Conclusions

Our study provides a comprehensive view of the exonic mutation profile of the largest pGI-DLBCL cohort to date. The results could facilitate the clinical development of novel therapeutic and prognostic biomarkers for pGI-DLBCL.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40164-022-00325-7.

MYD88L265P and CD79B double mutations type (MCD type) of diffuse large B-cell lymphoma: mechanism, clinical characteristics, and targeted therapy

MYD88/CD79B-mutated (MCD) genotype is a genetic subgroup of diffuse large B-cell lymphoma (DLBCL) with the co-occurrence of MYD88^L265P and CD79B mutations. MCD genotype is characterized by poor prognosis and extranodal involvement especially in immune-privileged sites. MCD model is dominated by activated B-cell (ABC)-like subtype of DLBCLs. It is generally accepted that the pathogenesis of MCD DLBCL mainly includes chronic active B-cell receptor (BCR) signaling and oncogenic MYD88 mutations, which drives pathological nuclear factor kappa B (NF-κB) activation in MCD lymphoid malignancies. CD79B and MYD88^L265P mutations are frequently and contemporaneously founded in B-cell malignancies. The collaboration of the two mutations may explain the unique biology of MCD. Meanwhile, standard immunochemotherapy combine with different targeted therapies worth further study to improve the prognosis of MCD, according to genetic, phenotypic, and clinical features of MCD type. In this review, we systematically described mechanism, clinical characteristics, and targeted therapy of MCD DLBCL.

Molecular Heterogeneity in Localized Diffuse Large B-Cell Lymphoma

The clinical and molecular characteristics of localized diffuse large B-cell lymphoma (DLBCL) with single nodal (SN) or single extranodal (SE) involvement remain largely elusive in the rituximab era. The clinical data of 181 patients from a retrospective cohort and 108 patients from a phase 3 randomized trial NHL-001 (NCT01852435) were reviewed. Meanwhile, genetic aberrations, gene expression pattern, and tumor immunophenotype profile were revealed by DNA and RNA sequencing of 116 and 53 patients, respectively. SE patients showed similar clinicopathological features as SN patients, except for an increased percentage of low-intermediate risk in the National Comprehensive Cancer Network–International Prognostic Index. According to the molecular features, increased MPEG1 mutations were observed in SN patients, while SE patients were associated with upregulation of TGF-β signaling pathway and downregulation of T-cell receptor signaling pathway. SE patients also presented immunosuppressive status with lower activity of killing of cancer cells and recruiting dendritic cells. Extranodal involvement had no influence on progression-free survival (PFS) or overall survival (OS) in localized DLBCL. Serum lactate dehydrogenase >3 upper limit of normal was an independent adverse prognostic factor for OS, and ATM mutations were related to inferior PFS. Although the overall prognosis is satisfactory, specific clinical, genetic, and microenvironmental factors should be considered for future personalized treatment in localized DLBCL.

Genomic Mutation Profile of Primary Gastrointestinal Diffuse Large B-Cell Lymphoma

Primary gastrointestinal diffuse large B-cell lymphoma (GI-DLBCL) is the most common gastrointestinal lymphoma, but its genetic features are poorly understood. We performed whole-exome sequencing of 25 primary tumor samples from patients with GI-DLBCL and 23 matched normal tissue samples. Oncogenic mutations were screened, and the correlations between genetic mutations and clinicopathological characteristics were analyzed. Twenty-five patients with GI-DLBCL were enrolled in the genetic mutation analysis with a median of 184 (range 79–382) protein-altering variants per patient. We identified recurrent oncogenic mutations in GI-DLBCL, including those in TP53, MUC16, B2M, CCND3, HIST1H1C, NEB, and ID3. Compared with nodal DLBCL, GI-DLBCL exhibited an increased mutation frequency of TP53 and reduced mutation frequencies of PIM1, CREBBP, BCL2, KMT2D, and EZH2. Moreover, GI-DLBCL exhibited fewer MYD88 and CD79B mutations than DLBCL in the testis and central nervous system. GI-DLBCLs with HLA-B, MEF2A, RHOA, and NAV3 mutations exhibited a tendency toward a high proliferation index. MUC16 and ETV6 mutations often occurred in tumors with early clinical staging. Our data provide a comprehensive understanding of the landscape of mutations in a small subset of GI-DLBCLs. The genetic mutation profiles of GI-DLBCL differ from those of nodal DLBCL and DLBCL in immune-privileged sites. The different mutated genes are related to the NF-κB and JAK-STAT pathways, and the different pathogenetic mechanisms leading to the development of DLBCL may be influenced by the tissue microenvironment. Differences in genetic alterations might influence the clinicopathological characteristics of GI-DLBCL.

Morphologic Patterns and the Correlation With MYD88 L265P, CD79B Mutations in Primary Adrenal Diffuse Large B-Cell Lymphoma

Primary adrenal diffuse large B-cell lymphoma (PA-DLBCL) is a rare subtype of extranodal DLBCL. Because of the rarity of this disease, its morphologic and genetic features are not comprehensively studied. Here, we systematically reviewed the clinicopathologic features of 42 cases of PA-DLBCL from our institution and investigated the frequency of MYD88 L265P and CD79B (exon 5) mutation in 29 eligible cases using Sanger sequencing. Clinically, PA-DLBCL was predominant in elderly male patients with advanced clinical stage and poor outcomes. Morphologically, the tumors often showed a sinusoidal and/or cohesive pattern with condensed chromatin and inconspicuous nucleolus which mimicked neuroendocrine carcinoma. Moreover, increased Reed-Sternberg-like cells were observed frequently. These confounding morphologic manifestations may lead to misdiagnosis. Genetically, PA-DLBCL harbored a high prevalence of MYD88 L265P (24%) and CD79B mutations (52%) which may be involved in lymphomagenesis. The CD79B mutation was significantly associated with a worse prognosis. A novel Histo-Molecular Classification system (4 categories) was proposed based on correlation with genetic changes. Generally, the neuroendocrine carcinoma-like type was associated with CD79B mutation, whereas the RS-like cell type indicated MYD88 L265P. The biphasic type was correlated with coexisting mutations of MYD88 and CD79B, whereas the common type implied no mutation. Furthermore, the common type showed significantly better survival. In conclusion, the proposed new category system could indicate the genetic changes as well as facilitate risk stratification to guide treatment and predict prognosis. Although this study augmented our understanding of PA-DLBCL, further analysis is required to validate our results and extend them to extranodal DLBCL at other sites.

Prognostic value of MYD88 L265P mutation in diffuse large B cell lymphoma via droplet digital PCR

To assess the prevalence and prognostic value of myeloid differentiation factor 88 (MYD88) expression and mutational status in diffuse large B cell lymphoma (DLBCL), a total cohort of 100 patients with DLBCL were studied using immunohistochemistry (IHC) and droplet digital polymerase chain reaction (DDPCR), and the association between MYD88 expression and clinicopathological parameters was analyzed. Overall, the positive expression rate of MYD88 protein was 38% and the gene mutation rate was 29%. The positive expression and mutation rates were the highest in the primary central nervous system lymphomas (58.33 and 66.67%, respectively). The coincidence rate of the results of MYD88 expression between IHC and DDPCR results was 73% (73/100). Univariate survival analysis showed that age (≥60 years old), high neutrophil/lymphocyte count ratio, low lymphocyte count, c-Myc ≥40%, positive MYD88 protein expression, and gene mutation were associated with poorer prognosis rates. Multivariate survival analysis revealed that MYD88 expression was an independent prognostic factor affecting overall survival. In conclusion, the results of this study demonstrated that MYD88 mutation was a valuable index to evaluate the prognosis of DLBCL. DDPCR can be used as a method for detecting MYD88 mutations, although it was not completely consistent with the results of IHC.

PD-L1+ tumor-associated macrophages and PD-1+ tumor-infiltrating lymphocytes predict survival in primary testicular lymphoma

Primary testicular lymphoma is a rare and aggressive lymphoid malignancy, most often representing diffuse large B-cell lymphoma histologically. Tumor-associated macrophages and tumor-infiltrating lymphocytes have been associated with survival in diffuse large B-cell lymphoma, but their prognostic impact in primary testicular lymphoma is unknown. Here, we aimed to identify macrophages, their immunophenotypes and association with lymphocytes, and translate the findings into survival of patients with primary testicular lymphoma. We collected clinical data and tumor tissue from 74 primary testicular lymphoma patients, and used multiplex immunohistochemistry and digital image analysis to examine macrophage markers (CD68, CD163, and c-Maf), T-cell markers (CD3, CD4, and CD8), B-cell marker (CD20), and three checkpoint molecules (PD-L1, PD-L2, and PD-1). We demonstrate that a large proportion of macrophages (median 41%, range 0.08–99%) and lymphoma cells (median 34%, range 0.1–100%) express PD-L1. The quantity of PD-L1⁺ CD68⁺ macrophages correlates positively with the amount of PD-1⁺ lymphocytes, and a high proportion of either PD-L1⁺ CD68⁺ macrophages or PD-1⁺ CD4⁺ and PD-1⁺ CD8⁺ T cells translates into favorable survival. In contrast, the number of PD-L1⁺lymphoma cells or PD-L1⁻ macrophages do not associate with outcome. In multivariate analyses with IPI, PD-L1⁺ CD68⁺ macrophage and PD-1⁺ lymphocyte contents remain as independent prognostic factors for survival. In conclusion, high PD-L1⁺ CD68⁺ macrophage and PD-1⁺ lymphocyte contents predict favorable survival in patients with primary testicular lymphoma. The findings implicate that the tumor microenvironment and PD-1 – PD-L1 pathway have a significant role in regulating treatment outcome. They also bring new insights to the targeted thera py of primary testicular lymphoma.

Extranodal Diffuse Large B Cell Lymphoma: Molecular Features, Prognosis, and Risk of Central Nervous System Recurrence

OPINION STATEMENT

Diffuse large B cell lymphoma (DLBCL) arises from extranodal organs in about 30% of cases. Its prognosis and risk of recurrence in the central nervous system (CNS) vary according to the primary site of origin. Recent studies begin to clarify these differences using molecular classification. Testicular, breast, and uterine DLBCL (as well as possibly primary cutaneous DLBCL, leg-type) share a high prevalence of the non-germinal center B cell (non-GCB) phenotype and the MYD88/CD79B-mutated (MCD) genotype. These biologic features, which resemble primary CNS lymphoma, may underlie their stage-independent propensity for CNS involvement. Management of these lymphomas should involve CNS prophylaxis, preferably using systemic high-dose methotrexate to prevent intraparenchymal recurrence. Involvement of the kidneys, adrenal glands, ovary, bone marrow, lung, or pleura usually indicates disseminated disease, conferring worse prognosis. Involvement of these sites is often associated with high CNS-International Prognostic Index (IPI), concurrent MYC and BCL2 or BCL6 rearrangements, or intravascular lymphoma-risk factors warranting CNS prophylaxis. In contrast, craniofacial, thyroid, localized bone, or gastric lymphomas have a variable prevalence of the non-GCB phenotype and lack MYD88 mutations. Their outcomes with standard immunochemotherapy are excellent, and the risk of CNS recurrence is low. We recommend individualized consideration of CNS prophylaxis based on the CNS-IPI score and anatomical proximity in cases of epidural, orbital, or skull involvement. Rituximab-containing immunochemotherapy is a standard approach for all extranodal DLBCLs. Surgery is no longer required for any primary site, but routine consolidative radiation therapy is recommended for testicular lymphoma. Radiation therapy also appears to be associated with better progression-free survival in primary bone DLBCL. Future studies should better distinguish primary from secondary sites of extranodal involvement, and investigate the association of newly identified genotypes with the risk of CNS or systemic recurrence.