Clinicopathologic implication of PD-L1 and phosphorylated STAT3 expression in diffuse large B cell lymphoma

Is There an Immunohistochemical PD-L1 Cut-Off Point That Serves as a Prognostic Indicator for Large B-Cell Lymphomas?

The aim of this study is to investigate whether there is a cut-off value for PD-L1 expression in large B-cell lymphomas that predicts prognosis, and to clarify the relationship between PD-L1 expression and histopathological as well as clinical parameters. The study included a total of 130 patients who were diagnosed with large B-cell lymphoma at Istanbul University-Cerrahpasa, Cerrahpasa Faculty of Medicine, Pathology Department. Biopsy samples were assessed using the PD-L1 immunohistochemical antibody (Dako, 22C3 clone). The patients had a mean age of 54 ± 17 years, with a median age of 56 years. No statistically significant difference was observed between the groups in terms of survival when the 30% cut-off value was used. However, a noteworthy discrepancy in survival became apparent when the cut-off point was established at 70%. Among the diffuse large B-cell lymphoma-not otherwise specified (DLBCL-NOS) category, the activated B-cell-like (ABC-like) phenotype showed higher PD-L1 expression compared to the germinal center B-cell-like (GCB-like) phenotype. Immunohistochemical PD-L1 expression emerged as a prognostic factor, particularly significant in the ABC-like phenotype.

Deciphering the Role of Epstein-Barr Virus Latent Membrane Protein 1 in Immune Modulation: A Multifaced Signalling Perspective

The disruption of antiviral sensors and the evasion of immune defences by various tactics are hallmarks of EBV infection. One of the EBV latent gene products, LMP1, was shown to induce the activation of signalling pathways, such as NF-κB, MAPK (JNK, ERK1/2, p38), JAK/STAT and PI3K/Akt, via three subdomains of its C-terminal domain, regulating the expression of several cytokines responsible for modulation of the immune response and therefore promoting viral persistence. The aim of this review is to summarise the current knowledge on the EBV-mediated induction of immunomodulatory molecules by the activation of signal transduction pathways with a particular focus on LMP1-mediated mechanisms. A more detailed understanding of the cytokine biology molecular landscape in EBV infections could contribute to the more complete understanding of diseases associated with this virus.

The prognostic significance of programmed cell death protein 1 and its ligand on lymphoma cells and tumor-immune cells in diffuse large B-cell lymphoma, not otherwise specified

BACKGROUND

Diffuse large B-cell lymphoma, not otherwise specified (DLBCL, NOS) is the most common type non-Hodgkin's lymphoma, where the treatment of relapsed/refractory cases is the major challenge. Programmed cell death protein 1 (PD-1) and its ligand PD-L1 play a crucial role in the negative regulation of the immune response against the disease. The aim of the study was to analyze the expression of PD-1 and PD-L1 on lymphoma cells (LCs) and tumor-immune cells (TICs) and to investigate their correlation with outcome.

PATIENTS AND METHODS

Samples from 283 patients diagnosed with DLBCL, NOS (both germinal center B cell like [GCB] and non-GCB subtypes) were included in the study. Expression of PD-1 and PD-L1 was determined using double immunohistochemical staining (D-IHC) for PD-1/PAX5 and PD-L1/PAX5 on tissue microarrays. LCs were highlighted by D-IHC to obtain more accurate results. Clinical data and histologic diagnoses were obtained from electronic data records. We correlated clinical characteristics, and PD-1 and PD-L1 expression on LCs and TICs with progression-free survival (PFS) and overall survival (OS).

RESULTS

Expression of PD-1 on TICs was observed in 38.4% and on LCs in 8.8% of cases, while PD-L1 was expressed on TICs in 46.8% and on LCs in 6.5% of cases. PD-L1 expression on LCs was more frequent in non-GCB subtype (p = 0.047). In addition, patients with PD-L1 expression on LCs had significantly shorter PFS (p = 0.015), and the expression retained significant in the multivariate model (p = 0.034).

CONCLUSIONS

PD-L1 was more frequently expressed in LCs of the non-GCB subtype. Additionally, PD-L1 in LCs may predict shorter PFS time. D-IHC staining for PD-L1/PAX5 is a feasible method to assess PD-L1 expression on LCs of DLBCL, NOS patients and can be used to identify patients who may benefit from targeted immunotherapy with checkpoint inhibitors.

Role and mechanism of PIM family in the immune microenvironment of diffuse large B cell lymphoma

BACKGROUND

Diffuse large B cell lymphoma (DLBCL) is a more common non-Hodgkin lymphoma (NHL). This study aims to explore the prognostic value of PIM kinase family in DLBCL and its relationship with the immune microenvironment, to provide a certain reference for the prognosis and treatment of DLBCL.

METHODS

The prognostic value of PIM kinase family in DLBCL from the data set GSE10846 was verified through survival analysis and cox regression analysis. Mutations in PIM kinase family and its relationship with immune cell infiltration were explored with online cBioPortal, TIMER database, and single-gene GSEA analysis. Finally, the expression of PIM kinase family in tissues from DLBCL clinical samples was validated through immunohistochemical staining.

RESULTS

The proteins of PIM kinase family were highly expressed in DLBCL patients, which are good prognostic factors for DLBCL patients. Then, PIM1-3 proteins were positively correlated with the immune infiltration of B cells, whose types of mutations also showed different degrees of correlation with B cells. PIM kinase family proteins also showed a high correlation with PDL1. In addition, PIM kinase family was also associated with the commonly mutated genes in DLBCL, such as MYD88, MYC, and BTK.

CONCLUSION

PIM kinase family may be a potential therapeutic target for DLBCL patients.

Visible- and near-infrared hyperspectral imaging for the quantitative analysis of PD-L1+ cells in human lymphomas: Comparison with fluorescent multiplex immunohistochemistry

INTRODUCTION

We analyzed the expression of PD-L1 in human lymphomas using hyperspectral imaging (HSI) compared to visual assessment (VA) and conventional digital image analysis (DIA) to strengthen further the value of HSI as a tool for the evaluation of brightfield-based immunohistochemistry (IHC). In addition, fluorescent multiplex immunohistochemistry (mIHC) was used as a second detection method to analyze the impact of a different detection method.

MATERIAL AND METHODS

18 cases (6 follicular lymphomas and 12 diffuse large B-cell lymphomas) were stained for PD-L1 by IHC and for PD-L1, CD3, and CD8 by fluorescent mIHC. The percentage of positively stained cells was evaluated with VA, HSI, and DIA for IHC and VA and DIA for mIHC. Results were compared between the different methods of detection and analysis.

RESULTS

An overall high concordance was found between VA, HSI, and DIA in IHC (Cohens Kappa = 0.810^VA/HSI, 0.710 ^VA/DIA, and 0.516 ^HSI/DIA) and for VA^mIHCversus DIA^mIHC (Cohens Kappa = 0.894). Comparing IHC and mIHC general agreement differed depending on the methods compared but reached at most a moderate agreement (Coheńs Kappa between 0.250 and 0.483). This is reflected by the significantly higher percentage of PD-L1+ cells found with mIHC (p^Friedman = 0.014).

CONCLUSION

Our study shows a good concordance for the different analysis methods. Compared to VA and DIA, HSI proved to be a reliable tool for assessing IHC. Understanding the regulation of PD-L1 expression will further enlighten the role of PD-L1 as a biomarker. Therefore it is necessary to develop an instrument, such as HSI, which can offer a reliable and objective evaluation of PD-L1 expression.

Bcl-6-dependent risk stratification by nuclear expression of Peli1 in diffuse large B-cell lymphoma

Background/Aim: Peli1 is an E3 ubiquitin ligase involving lymphomagenesis by lysine 63 ubiquitination-mediated stabilization of Bcl-6 with in diffuse large B-cell lymphoma (DLBCL). Materials and Methods: We categorized nuclear expression of Peli1 according to Bcl-6 status by immunohistochemistry in DLBCL (n=100), and analyzed clinicopathologic association with prognosis. Results: We established Bcl-6/Peli1 risk model composed of high risk (Bcl-6+/Peli1+ or Bcl-6-/Peli1-; n=64) and low risk (Bcl-6+/Peli1- or Bcl-6-/Peli1+; n=36). High risk group had more frequent non-GCB subtype (83% vs 64%; p=0.033) and Bcl-6-negativity (69% vs 28%; p<0.001) than low risk group. Univariate survival analysis for progression-free survival (PFS) and overall survival (OS) revealed Bcl-6/Peli1 risk group (p=0.026 and p=0.021) and other conventional variables including international prognostic index (IPI), stage, ECOG performance status, number of extranodal sites were significant prognostic factors, along with B symptoms for OS. In multivariate analysis for PFS, Bcl-6/Peli1 risk group (p=0.032; HR=3.29), IPI (p=0.013; HR=3.39) and ECOG PS (p=0.035; HR=3.08) were independent prognostic factors. In multivariate analysis for OS, Bcl-6/Peli1 risk group (p=0.048; HR=7.87) and IPI (p=0.001; HR=12.15) were associated with prognosis. Conclusions: DLBCL had distinctive risk groups according to pairs of nuclear Peli1 and Bcl-6 expression. These results suggest the potential role of Peli1 and Bcl-6 in risk assessment in DLBCL.

PD-1/PD-L1 Pathway: A Therapeutic Target in CD30+ Large Cell Lymphomas

The programmed death-ligands, PD-L1 and PD-L2, reside on tumor cells and can bind with programmed death-1 protein (PD-1) on T-cells, resulting in tumor immune escape. PD-1 ligands are highly expressed in some CD30+ large cell lymphomas, including classic Hodgkin lymphoma (CHL), primary mediastinal large B-cell lymphoma (PMBL), Epstein–Barr virus (EBV)-positive diffuse large B-cell lymphoma (EBV+ DLBCL), and anaplastic large cell lymphoma (ALCL). The genetic alteration of the chromosome 9p24.1 locus, the location of PD-L1, PD-L2, and JAK2 are the main mechanisms leading to PD-L1 and PD-L2 overexpression and are frequently observed in these CD30+ large cell lymphomas. The JAK/STAT pathway is also commonly constitutively activated in these lymphomas, further contributing to the upregulated expression of PD-L1 and PD-L2. Other mechanisms underlying the overexpression of PD-L1 and PD-L2 in some cases include EBV infection and the activation of the mitogen-activated protein kinase (MAPK) pathway. These cellular and molecular mechanisms provide a scientific rationale for PD-1/PD-L1 blockade in treating patients with relapsed/refractory (R/R) disease and, possibly, in newly diagnosed patients. Given the high efficacy of PD-1 inhibitors in patients with R/R CHL and PMBL, these agents have become a standard treatment in these patient subgroups. Preliminary studies of PD-1 inhibitors in patients with R/R EBV+ DLBCL and R/R ALCL have also shown promising results. Future directions for these patients will likely include PD-1/PD-L1 blockade in combination with other therapeutic agents, such as brentuximab or traditional chemotherapy regimens.

Enhanced PD-L1 Expression in LMP1-positive Cells of Epstein-Barr Virus-associated Malignant Lymphomas and Lymphoproliferative Disorders: A Single-cell Resolution Analysis With Multiplex Fluorescence Immunohistochemistry and In Situ Hybridization

Epstein-Barr virus (EBV) is associated with various types of human malignancies and with programmed death ligand (PD-L) 1 expression in neoplastic cells. However, in EBV-associated malignant lymphomas and lymphoproliferative disorders (LPDs), there is limited information regarding PD-L1 expression profiles among different histologic types and patterns of EBV latency. First, we investigated PD-L1 and EBV latent gene expression using conventional immunohistochemistry and in situ hybridization in 42 EBV-associated malignant lymphomas and LPDs. Classic Hodgkin lymphoma showed the highest PD-L1 expression with diffuse expression in all cases, followed by diffuse large B-cell lymphoma/Burkitt lymphoma, LPDs, and extranodal NK/T-cell lymphoma. EBV latency at the case level was not associated with PD-L1 expression. We further evaluated the expression of PD-L1 and EBV latent genes in tumor cells at single-cell resolution using multiplex fluorescence imaging. This analysis revealed that positivity rates of latent membrane protein (LMP) 1 in tumor cells were 1.0% to 89.5% (mean 35.4%) in latency type II/III cases, and LMP1+ cells showed more frequent PD-L1 expression than LMP1- cells (P<0.0001, paired t test). In contrast, no association was observed between EBV nuclear antigen 2 and PD-L1 expression. Notably, tumor cells exhibiting Hodgkin/Reed-Sternberg cell-like morphology co-expressed PD-L1 and LMP1 more often than those that do not. Our observations suggested that LMP1 upregulates PD-L1 expression and is a potential biomarker for predicting the efficacy of immune checkpoint inhibitors. In addition, the heterogeneous expression of PD-L1 and EBV latent genes may produce diverse tumor cells with different oncogenic and immune-evasive properties, leading to resistance to targeted therapies.

Clinicopathologic implication of PD-L1 gene alteration in primary adrenal diffuse large B cell lymphoma

Background

Primary adrenal (PA) diffuse large B cell lymphoma (DLBCL) was previously reported as an aggressive subset of DLBCL, but its genetic features were not sufficiently characterized. From our previous study of DLBCL with programmed death-ligand 1 (PD-L1) gene alterations, we focused on PD-L1 gene alterations in PA-DLBCL with clinicopathologic implications.

Methods

We performed fluorescence in situ hybridization for PD-L1 gene translocation and amplification in PA-DLBCL (n = 18) and comparatively analyzed clinicopathologic characteristics with systemic non-adrenal (NA)-DLBCL (n = 90).

Results

PA-DLBCL harbored distinctive features (vs. NA-DLBCL), including high international prognostic index score (3–5) (72% [13/18] vs. 38% [34/90], p = .007), poor Eastern Cooperative Oncology Group performance score (≥ 2) (47% [7/15] vs. 11% [10/90], p = .003), elevated serum lactate dehydrogenase (LDH) (78% [14/18] vs. 51% [44/87], p = .035) and MUM1 expression (87% [13/15] vs. 60% [54/90], p = .047). Moreover, PA-DLBCL showed frequent PD-L1 gene alterations (vs. NA-DLBCL) (39% [7/18] vs. 6% [5/86], p = .001), including translocation (22% [4/18] vs. 3% [3/87], p = .016) and amplification (17% [3/18] vs. 2% [2/87], p = .034). Within the PA-DLBCL group, PD-L1 gene–altered cases (vs. non-altered cases) tended to have B symptoms (p = .145) and elevated LDH (p = .119) but less frequent bulky disease (≥ 10 cm) (p = .119). In the survival analysis, PA-DLBCL had a poor prognosis for overall survival (OS) and progression-free survival (PFS) (vs. NA-DLBCL; p = .014 and p = .004). Within the PA-DLBCL group, PD-L1 translocation was associated with shorter OS and PFS (p < .001 and p = .012).

Conclusions

PA-DLBCL is a clinically aggressive and distinct subset of DLBCL with frequent PD-L1 gene alterations. PD-L1 gene translocation was associated with poor prognosis in PA-DLBCL.

The Positivity of Phosphorylated STAT3 Is a Novel Marker for Favorable Prognosis in Germinal Center B-Cell Type of Diffuse Large B-Cell Lymphoma

On the basis of immunohistochemistry, diffuse large B-cell lymphoma (DLBCL) is categorized as a germinal center B-cell (GCB) or non-GCB subtype. Recent integrated genomic analyses have highlighted the importance of the JAK-STAT3 pathway in the molecular pathogenesis of DLBCL. However, its relevance to clinical outcomes remains controversial. Therefore, we evaluated the extent of the nuclear expression of phosphorylated STAT3 (pSTAT3), a surrogate marker of signal transducer and activator of transcription 3 (STAT3) activation, by immunohistochemistry. We also analyzed the potential relationship between pSTAT3 positivity (defined as ≥40% positive neoplastic cells) and clinicopathologic characteristics in 294 patients with DLBCL. pSTAT3 was detected in 122 patients (42%), with a higher rate in the non-GCB subtype than in the GCB subtype (57% vs. 28%, P<0.001). Factors potentially activating STAT3, MYD88L265P, and Epstein-Barr virus-encoded small RNA were identified in the pSTAT3-positive non-GCB subtype, whereas the pSTAT3-positive GCB subtype often showed STAT3 mutations and lacked EZH2 mutations and the rearrangements of BCL2 and MYC. Multivariate analyses revealed that the pSTAT3-positive GCB subtype showed a favorable prognosis (HR: 0.17; 95% confidence interval, 0.04-0.7; P=0.014). These findings suggest that pSTAT3 positivity may have a unique impact on the clinicopathologic characteristics of DLBCL, making it a promising novel marker for the favorable prognosis of patients with the GCB subtype.

Clinicopathologic significance of MYD88 L265P mutation and expression of TLR4 and P-STAT3 in primary central nervous system diffuse large B-cell lymphomas

Patients with primary central nervous system lymphoma (PCNSL) have a prognosis poorer than that of systemic lymphoma patients. In patients with this condition, TLR4/STAT3 pathway alterations and the MYD88 L265P mutation may be viable targets for therapeutic intervention. The present study was, therefore, designed to identify clinicopathologic correlates of MYD88 mutations and TLR4/STAT3 pathway alterations in PCNSL. We detected TLR4 and p-STAT3 in 41.5% (22/53) and 43.4% (23/53) of PCNSL patients, respectively, while 60.4% of these patients (32/53) were found to harbor the MYD88 L265P mutation. TLR4 expression was found to be significantly associated with the presence of multiple brain lesions, while p-STAT3 expression was significantly linked to advanced age, the presence of multiple brain lesions, non-GCB histological findings, and non-CR status. The presence of the MYD88 L265P mutation was significantly linked to advanced age, the presence of multiple brain lesions, and DLBCL molecular subtype. Multivariate analyses additionally confirmed that elevated TLR4 and p-STAT3 expression levels are associated with a poorer PCNSL patient prognosis. Based on these findings, we hypothesize that signaling through the TLR4/MYD88/STAT3 pathway plays a key role in the pathogenesis of PCNSL.

Plasma soluble PD-L1 and STAT3 predict the prognosis in diffuse large B cell lymphoma patients

Purpose: Diffuse large B cell lymphoma (DLBCL) is one of the most common B cell lymphomas, which displays heterogeneous pathologies. Programmed cell death 1/ programmed cell death ligand 1 (PD-1/PD-L1) plays an essential role in immunosuppression in multiple malignancies. Signal transducer and activator of transcription 3 (STAT3)-positive patients also have an independently inferior clinical outcome. However, there are no reports on the effect of plasma soluble PD-L1 (sPD-L1) combined with plasma STAT3 on the prognosis of DLBCL. In this study, we investigate the relationships between plasma sPD-L1 combined with STAT3 and clinical prognosis of DLBCL.

Methods: Levels of plasma sPD-L1 and STAT3 were quantified using ELISA in eighty-seven DLBCL patients. Multiplexed immunofluorescence staining was performed to visualize the expression of PD-L1 in twenty-nine matched FFPE specimens from all patients.

Results: The survival analysis revealed that the progression-free survival (PFS) and overall survival (OS) in high sPD-L1 level group were poorer than that in low sPD-L1 level group (PFS, P < 0.001; OS, P < 0.001). Similarly, the PFS and OS in high STAT3 level group were also poorer than that in low STAT3 level group. Multivariate cox regression analysis showed that both high sPD-L1 and high STAT3 levels were the independent prognostic factors negatively affecting survival. In addition, patients with DLBCL having high levels of both sPD-L1 and STAT3 had a worse outcome than those patients having any one high or low levels of both (P < 0.001).

Conclusions: We therefore revealed that high levels of plasma sPD-L1 and STAT3 are associated with inferior outcome for DLBCL patients, suggesting that combined measurement of their levels in plasma may be a promising prognostic strategy for DLBCL patients.

Extranodal site of diffuse large B-cell lymphoma and the risk of R-CHOP chemotherapy resistance and early relapse

BACKGROUND

About 20%-30% of diffuse large B-cell lymphoma (DLBCL) patients experience early disease progression despite R-CHOP chemotherapy treatment. Revised international prognostic index (R-IPI) score could risk stratify DLBCL patients but does not identify exactly which patient will be resistant to R-CHOP therapy or experience early relapse.

AIMS OF THE STUDY

To analyse pre-treatment clinical features of DLBCL patients that are predictive of R-CHOP therapy resistance and early disease relapse after R-CHOP therapy treatment.

METHODS USED TO CONDUCT THE STUDY

A total of 698 lymphoma patients were screened and 134 R-CHOP-treated DLBCL patients were included. The Lugano 2014 criteria was applied for assessment of treatment response. DLBCL patients were divided into R-CHOP resistance/early relapse group and R-CHOP sensitive/late relapse group.

RESULTS OF THE STUDY

81 of 134 (60%) were R-CHOP sensitive/late relapse, while 53 (40%) were R-CHOP resistance/early relapse. The median follow-up period was 59 months ± standard error 3.6. Five-year overall survival rate of R-CHOP resistance/early relapse group was 2.1%, while it was 89% for RCHOP sensitive/late relapse group. Having more than one extranodal site of DLBCL disease is an independent risk factor for R-CHOP resistance/early relapse [odds ratio = 5.268 (1.888-14.702), P = .002]. The commonest extranodal sites were head and neck, gastrointestinal tract, respiratory system, vertebra and bones. Advanced age (>60 years), advanced disease stage (lll-lV), raised pre-treatment lactate dehydrogenase level, bone marrow involvement of DLBCL disease high Eastern Cooperative Oncology Group status (2-4) and high R-IPI score (3-5) showed no significant association with R-CHOP therapy resistance/early disease relapse (multivariate analysis: P > .05).

CONCLUSION AND CLINICAL IMPLICATIONS

DLBCL patients with more than one extranodal site are 5.268 times more likely to be R-CHOP therapy resistance or experience early disease relapse after R-CHOP therapy. Therefore, correlative studies are warranted in DLBCL patients with more than one extranodal site of disease to explore possible underlying mechanisms of chemoresistance.

The influence of programmed cell death ligand 2 (PD-L2) expression on survival outcome and tumor microenvironment in diffuse large B cell lymphoma

The frequency and significance of programmed cell death ligand (PD-L) 2 expression in diffuse large B cell lymphoma (DLBCL) remain undefined. We described the expression pattern of PD-L/PD-1 in 88 DLBCL patients using immunohistochemistry. The association between PD-L expression and clinical characteristics/outcomes were analyzed. PD-L1 and PD-L2 were expressed in 14.8% and 68.2% of DLBCL patients with median positivity on tumor cells of 100% and 90%, respectively. PD-1 on tumor-infiltrating lymphocytes (TILs) was expressed in 12.5% of patients. Interestingly, 45.5% of patients had PD-L2 expressing TILs which were significantly associated with bulky disease (p = .046) and elevated lactate dehydrogenase (p = .048). PD-L1 and/or PD-L2 expression on lymphoma cells was associated with inferior progression-free survival (Hazard ratio [HR] 2.20; 95% Confidence Interval [CI] 1.004-4.84, p = .049) and overall survival (HR 2.27; 95%CI 1.03-4.98, p = .042), using multivariate analysis. In summary, PD-L2 expression on DLBCL is common and, together with PD-L1, were related to poor outcomes.

PD-L1 Is Expressed and Promotes the Expansion of Regulatory T Cells in Acute Myeloid Leukemia

Intratumoral accumulation of CD4⁺CD25⁺Foxp3⁺ regulatory T (Treg) cells occurs in acute myeloid leukemia (AML), but little is known about the role of tumor cells themselves in this process. Here, we showed that an immune checkpoint PD-L1 expressed by AML cells promoted the conversion and expansion of Treg cells sustaining high expression of Foxp3 and PD-1 as well as a suppressive function. Furthermore, an AML cell line HEL overexpressed PD-L1 promoted the conversion and expansion of Treg cells and CD4⁺PD-1⁺Foxp3⁺ T (PD-1⁺Treg) cells from the conventional CD4⁺ T cells. CD4⁺CD25^highPD-1⁺ T cells secreted more IL-10 production than CD4⁺CD25^highPD-1⁻ T cells. IL-35, another cytokine secreted by Treg cells, promoted the proliferation of HL-60 cells and enhanced chemoresistance to cytarabine. Blockade of PD-1 signaling using anti-PD-L1 antibody dramatically impaired the generation of Treg cells and sharply retarded the progression of a murine AML model injected with C1498 cells. The frequency of intratumoral PD-1⁺ Treg cells was capable of predicting patient survival in patients with AML. In conclusion, our data suggest that PD-L1 expression by AML cells may directly drive Treg cell expansion as a mechanism of immune evasion and the frequency of PD-1⁺ Treg cells is a potential prognostic predictor in patients with AML.

PD-L1 (SP142) expression in neoplastic cells predicts a poor prognosis for patients with intravascular large B-cell lymphoma treated with rituximab-based multi-agent chemotherapy

Background

Intravascular large B‐cell lymphoma (IVLBCL) is a rare form of diffuse large B‐cell lymphoma (DLBCL) arising in extranodal sites. PD‐L1 expression of tumor cells has been reported in IVLBCL cells, but its clinicopathological relevance remains to be elucidated.

Aims

This study was aimed to reveal the characteristics of PD‐L1⁺ IVLBCL.

Methods and results

Neoplastic PD‐L1 expression was examined in 34 cases of IVLBCL and clinicopathological characteristics between patients with PD‐L1⁺ and PD‐L1⁻ IVLBCL were compared. We assessed PD‐L1 expression with SP142 antibody. Twelve (35%) of 34 cases showed positivity for PD‐L1. The PD‐L1⁺ group had significantly lower survival rates compared to the PD‐L1⁻ group. The PD‐L1⁺ IVLBCL group also had a significantly lower age distribution and a lower frequency of patients older than 60 years compared to the PD‐L1⁻ group. Very recently, we speculate that there is possible link between PD‐L1⁺ IVLBCL and PD‐L1⁺ extranodal DLBCL‐NOS (eDLBCL) because features of the two groups showed overlapping. Therefore, we compared the clinicopathological characteristics of the PD‐L1⁺ IVLBCL and PD‐L1⁺ eDLBCL. There were no significant differences in clinicopathological parameters and prognosis.

Conclusion

The worse prognosis of the PD‐L1⁺ group might be caused by immune evasion mechanisms, which are linked to PD‐L1 expression. Therefore, PD‐L1⁺ IVLBCL cases might be regarded as good candidates for targeted immunotherapy. We also highlighted the overlapping features of PD‐L1⁺ IVLBCL and PD‐L1⁺ eDLBCL. This result suggests that they should be regarded as one entity, immune evasion‐related extranodal large B‐cell lymphoma.

The prognostic and clinicopathological significance of PD-L1 expression in patients with diffuse large B-cell lymphoma: a meta-analysis

BACKGROUND

Programmed cell death receptor 1 ligand 1 (PD-L1) expression in various tumors, including hematologic malignancies, has recently become a research topic of great interest. We performed a meta-analysis to evaluate the prognostic and clinicopathological value of PD-L1 expressed in tumor cells of patients with diffuse large B-cell lymphoma (DLBCL).

METHODS

Relevant studies were identified from PubMed, EMBASE, Web of Science and the Cochrane Library. The hazard ratio (HR) and 95% confidence interval (95% CI) were used for analyzing survival outcomes, and the odds ratio (OR) was used for analyzing clinicopathological parameters.

RESULTS

Pooled results showed that tumor cell PD-L1 expression is associated with poor overall survival (OS) (HR = 2.128, 95% CI: 1.341-3.378, P = 0.001), the non-germinal center B-cell-like subtype (OR = 2.891, 95% CI: 2.087-4.003, P < 0.000), high international prognostic index score (3-5) (OR = 1.552, 95% CI: 1.111-2.169, P = 0.010), B symptoms (OR = 1.495, 95% Cl: 1.109-2.015, P = 0.008), positive MUM1 expression (OR = 3.365, 95% Cl: 1.578-7.175, P = 0.002) and negative BCL6 expression (OR = 0.414, 95% Cl: 0.217-0.792, P = 0.008). Sensitivity analysis showed that there was no publication bias among these studies.

CONCLUSIONS

Our meta-analysis supported the idea that tumor cell PD-L1 expression may represent a promising biomarker for predicting poor prognosis and is associated with adverse clinicopathologic features in DLBCL patients.