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

Low Absolute Lymphocyte Counts in the Peripheral Blood Predict Inferior Survival and Improve the International Prognostic Index in Testicular Diffuse Large B-Cell Lymphoma

Low absolute lymphocyte counts (ALC) and high absolute monocyte counts (AMC) are associated with poor survival in patients with diffuse large B-cell lymphoma (DLBCL). We studied the prognostic impact of the ALC and AMC in patients with testicular DLBCL (T-DLBCL). T-DLBCL patients were searched using Southern Finland University Hospital databases and the Danish lymphoma registry. The progression free survival (PFS) and overall survival (OS) were assessed using Kaplan-Meier and Cox proportional hazards methods. We identified 178 T-DLBCL patients, of whom 78 (44%) had a low ALC at diagnosis. The ALC did not correlate with survival in the whole cohort. However, among the patients treated with rituximab (R) containing regimen, a pre-therapeutic low ALC was associated with an increased risk of progression (HR 1.976, 95% CI 1.267–3.086, p = 0.003). Conversely, intravenous (iv) CNS directed chemotherapy translated to favorable outcome. In multivariate analyses, the advantage of an iv CNS directed chemotherapy was sustained (PFS, HR 0.364, 95% CI 0.175–0.757, p = 0.007). The benefit of R and intravenous CNS directed chemotherapy was observed only in non-lymphopenic patients. The AMC did not correlate with survival. A low ALC is an adverse prognostic factor in patients with T-DLBCL. Alternative treatment options for lymphopenic patients are needed.

PD-L1 and PD-L2 expression in the tumor microenvironment including peritumoral tissue in primary central nervous system lymphoma

Background

The prevalence of programmed death-ligand 1 (PD-L1) and PD-L2 expression on tumor cells and tumor-infiltrating immune cells in primary central nervous system lymphoma (PCNSL) remains unclear. In the present study, we analyzed needle biopsy and craniotomy specimens of patients with PCNSL to compare the PD-L1 and PD-L2 levels in the tumor and surrounding (peritumoral) tissue. We also assessed the correlation between biological factors and the prognostic significance of PD-L1 and PD-L2 expression.

Methods

We retrospectively analyzed the cases of 70 patients histologically diagnosed with PCNSL (diffuse large B-cell lymphoma). Immunohistochemistry for CD20, CD68, PD-L1, and PD-L2 was performed. In cases with specimens taken by craniotomy, the percentages of PD-L1- and PD-L2-positive macrophages were evaluated in both tumor and peritumoral tissue. The Kaplan-Meier method with log-rank test and Cox proportional hazard model were used for survival analysis.

Results

The tumor cells expressed little or no PD-L1 and PD-L2, but macrophages expressed PD-L1 and PD-L2 in most of the patients. The median percentage of PD-L2-positive cells was significantly higher among peritumoral macrophages (32.5%; 95% CI: 0–94.6) than intratumoral macrophages (27.5%; 95% CI: 0–81.1, p = 0.0014). There was a significant correlation between the percentages of PD-L2-positive intratumoral macrophages and PD-L2-positive peritumoral macrophages (p = 0.0429), with very low coefficient correlation (ρ = 0.098535). PD-L1 expression on macrophages was significantly associated with biological factors (intratumoral macrophages: better KPS, p = 0.0008; better MSKCC score, p = 0.0103; peritumoral macrophages: low proportion of LDH elevation, p = 0.0064) and longer OS (for intratumoral macrophages: high PD-L1 = 60 months, 95% CI = 30–132.6; low PD-L1 = 24 months, 95% CI = 11–48; p = 0.032; for peritumoral macrophages: high PD-L1 = 60 months, 95% CI = 30.7–NR; low PD-L1 = 14 months, 95% CI = 3–26). PD-L1 expression on peritumoral macrophages was strongly predictive of a favorable outcome (HR = 0.30, 95% CI = 0.12–0.77, p = 0.0129).

Conclusions

Macrophages in intratumoral and peritumoral tissue expressed PD-L1 and PD-L2 at a higher rate than tumor cells. PD-L1 expression, especially on peritumoral macrophages, seems to be an important prognostic factor in PCNSL. Future comprehensive analysis of checkpoint molecules in the tumor microenvironment, including the peritumoral tissue, is warranted.

Prognostic Impact of Tumor-Associated Macrophages on Survival Is Checkpoint Dependent in Classical Hodgkin Lymphoma

Tumor microenvironment and immune escape affect pathogenesis and survival in classical Hodgkin lymphoma (cHL). While tumor-associated macrophage (TAM) content has been associated with poor outcomes, macrophage-derived determinants with clinical impact have remained undefined. Here, we have used multiplex immunohistochemistry and digital image analysis to characterize TAM immunophenotypes with regard to expression of checkpoint molecules programmed cell death ligand 1 (PD-L1) and indoleamine 2,3-dioxygenase 1 (IDO-1) from the diagnostic tumor tissue samples of 130 cHL patients, and correlated the findings with clinical characteristics and survival. We show that a large proportion of TAMs express PD-L1 (CD68⁺, median 32%; M2 type CD163⁺, median 22%), whereas the proportion of TAMs expressing IDO-1 is lower (CD68⁺, median 5.5%; CD163⁺, median 1.4%). A high proportion of PD-L1 and IDO-1 expressing TAMs from all TAMs (CD68⁺), or from CD163⁺ TAMs, is associated with inferior outcome. In multivariate analysis with age and stage, high proportions of PD-L1⁺ and IDO-1⁺ TAMs remain independent prognostic factors for freedom from treatment failure (PD-L1⁺CD68⁺/CD68⁺, HR = 2.63, 95% CI 1.17–5.88, p = 0.019; IDO-1⁺CD68⁺/CD68⁺, HR = 2.48, 95% CI 1.03–5.95, p = 0.042). In contrast, proportions of PD-L1⁺ tumor cells, all TAMs or PD-L1⁻ and IDO-1⁻ TAMs are not associated with outcome. The findings implicate that adverse prognostic impact of TAMs is checkpoint-dependent in cHL.

Primary testicular diffuse large B-cell lymphoma: Case series

RATIONALE

Primary testicular lymphoma (PTL) is a rare type of extranodal non-Hodgkin's lymphoma (NHL). Although data of PTL in patients with diffuse large B-cell lymphoma (DLBCL) are accumulating, there are still patients respond poorly to prognosis.

PATIENT CONCERNS

All patients had disease of the DLBCL subtype and those patients had primary involvement of the testis. In our studies, eleven patients had stage I/II disease, and 3 patients had advanced disease with B symptoms. Four patients exhibited a MYC+, BCL2+, and BCL6- expression pattern, 4 patients had a MYC+, BCL6+, and BCL2- expression pattern, and 3 patients had a MYC+, BCL2+, and BCL6+ expression pattern. Additionally, 43% (7/16) of PT-DLBCL patients had a germinal center B-cell-like (GCB) phenotype, while the others had a non-GCB phonotype.

DIAGNOSES

In our case, most patients presented with unilateral painless scrotal swelling and the enlargement of the testicles in the first examination. After hospitalization, all patients underwent preoperative imageological examination of the testis and epididymis and postoperative revealed that all patients were the diffuse infiltration of a large number of anomalous lymphocytes. In addition, no invasion of other sites was observed within 3 months after diagnosis.

INTERVENTIONS AND OUTCOMES

Underwent orchiectomy on the affected side was performed by urologists after all patients were diagnosed with PTL. Meanwhile, some patients received at least one course of chemotherapy, or received postoperative combined RT and chemotherapy. Because of it particularity, nineteen instances of lymph node region involvement were discovered in 12 patients since the operation.

LESSONS

PT-DLBCL has unique biological characteristics, and its treatment modalities are becoming increasingly standardized. In the future, systematic interventions need to be actively considered in the early stages of PTL.

Primary CNS lymphoma commonly expresses immune response biomarkers

Background

Primary central nervous system lymphoma (PCNSL) is rare and there is limited genomic and immunological information available. Incidental clinical and radiographic responses have been reported in PCNSL patients treated with immune checkpoint inhibitors.

Materials and Methods

To genetically characterize and ascertain if the majority of PCNSL patients may potentially benefit from immune checkpoint inhibitors, we profiled 48 subjects with PCNSL from 2013 to 2018 with (1) next-generation sequencing to detect mutations, gene amplifications, and microsatellite instability (MSI); (2) RNA sequencing to detect gene fusions; and (3) immunohistochemistry to ascertain PD-1 and PD-L1 expression. Tumor mutational burden (TMB) was calculated using somatic nonsynonymous missense mutations.

Results

High PD-L1 expression (>5% staining) was seen in 18 patients (37.5%), and intermediate expression (1-5% staining) was noted in 14 patients (29.2%). Sixteen patients (33.3%) lacked PD-L1 expression. PD-1 expression (>1 cell/high-power field) was seen in 12/14 tumors (85.7%), uncorrelated with PD-L1 expression. TMB of greater than or equal to 5 mutations per megabase (mt/Mb) occurred in 41/42 tumors, with 19% (n = 8) exhibiting high TMB (≥17 mt/Mb), 71.4% (n = 30) exhibiting intermediate TMB (7-16 mt/Mb), and 9.5% (n = 4) exhibiting low TMB (≤6 mt/Mb). No samples had MSI. Twenty-six genes showed mutations, most frequently in MYD88 (34/42, 81%), CD79B (23/42, 55%), and PIM1 (23/42, 55%). Among 7 cases tested with RNA sequencing, an ETV6-IGH fusion was found. Overall, 18/48 samples expressed high PD-L1 and 38/42 samples expressed intermediate to high TMB.

Conclusions

Based on TMB biomarker expression, over 90% of PCNSL patients may benefit from the use of immune checkpoint inhibitors.

c-Cbl targets PD-1 in immune cells for proteasomal degradation and modulates colorectal tumor growth

Casitas B lymphoma (c-Cbl) is an E3 ubiquitin ligase and a negative regulator of colorectal cancer (CRC). Despite its high expression in immune cells, the effect of c-Cbl on the tumor microenvironment remains poorly understood. Here we demonstrate that c-Cbl alters the tumor microenvironment and suppresses Programmed cell death-1 (PD-1) protein, an immune checkpoint receptor. Using syngeneic CRC xenografts, we observed significantly higher growth of xenografts and infiltrating immune cells in c-Cbl^+/− compared to c-Cbl^+/+ mice. Tumor-associated CD8+ T-lymphocytes and macrophages of c-Cbl^+/− mice showed 2–3-fold higher levels of PD-1. Functionally, macrophages from c-Cbl^+/− mice showed a 4–5-fold reduction in tumor phagocytosis, which was restored with an anti-PD-1 neutralizing antibody suggesting regulation of PD-1 by c-Cbl. Further mechanistic probing revealed that C-terminus of c-Cbl interacted with the cytoplasmic tail of PD-1. c-Cbl destabilized PD-1 through ubiquitination- proteasomal degradation depending on c-Cbl’s RING finger function. This data demonstrates c-Cbl as an E3 ligase of PD-1 and a regulator of tumor microenvironment, both of which were unrecognized components of its tumor suppressive activity. Advancing immune checkpoint and c-Cbl biology, our study prompts for probing of PD-1 regulation by c-Cbl in conditions driven by immune checkpoint abnormalities such as cancers and autoimmune diseases.

Validation and characterisation of prognostically significant PD-L1+ immune cells in HPV+ oropharyngeal squamous cell carcinoma

We previously showed in human papillomavirus positive oropharyngeal squamous cell carcinoma (HPV+OPSCC) that the presence of intratumoral (IT) PD-L1⁺ immune cells (ICs) or CD8⁺ infiltrating ICs are of prognostic value. Here we report the prognostic significance of these immune biomarkers in an independent validation cohort of 177 HPV+OPSCC patients. IT and stromal (S) localisation of PD-L1⁺ and CD8⁺ ICs were scored. High abundance (≥5%) of PD-L1⁺ IT ICs was found in 51/167 patients (30.5%) and was associated with improved overall survival (OS) (HR, 0.21; 95% CI, 0.05-0.91; P = 0. 012) validating our previous results. High abundance (≥30%) of CD8⁺ IT or S ICs, found in 77/167 patients (46.1%) provided a HR of 0.45 for OS however the confidence interval was wide (95% CI 0.16-1.25, p = 0.105). Multiplex immunohistochemistry revealed CD68⁺ macrophages and CD3⁺CD8⁺ T cells to be the most common ICs expressing PD-L1. Gene expression analysis showed tumors with high abundance of PD-L1⁺ IT ICs exhibit gene signatures associated with responses to PD1 or PD-L1 inhibitors pembrolizumab and atezolizumab. These data support the role of immune biomarkers such as PD-L1⁺ ICs to identify subgroups of HPV+OPSCC patients with an excellent outcome that may be suitable for trials evaluating de-intensification of therapy.

Characterisation of tumour microenvironment and immune checkpoints in primary central nervous system diffuse large B cell lymphomas

Primary central nervous system diffuse large B cell lymphoma (PCNS-DLBCL) is a rare and aggressive entity of diffuse large B cell lymphoma (DLBCL). Elements of the tumour microenvironment (TME) including tumour-infiltrating lymphocytes (TILs) and tumour-associated macrophages (TAMs) have been associated with survival in DLBCL but their composition and prognostic impact in PCNS-DLBCL are unknown. Programmed cell death-1 (PD1)/programmed death-ligand 1 (PD-L1) immune checkpoint may represent a therapeutic option. Here, we aimed to characterise PD1/PDL1 immune checkpoints and the composition of the TME in PCNS-DLBCL. We collected tumour tissue and clinical data from 57 PCNS-DLBCL and used immunohistochemistry to examine TAMs (CD68, CD163), TILs (CD3, CD4, CD8, PD1) and tumour B cells (PAX5/PDL1 double stains, PDL1). The PDL1 gene was evaluated by fluorescence in situ hybridization (FISH). PAX5/PDL1 identified PDL1 expression by tumour B cells in 10/57 cases (17.5%). PDL1 gene translocation was a recurrent cytogenetic alteration in PNCS-DLBCL (8/47.17%) and was correlated with PDL1 positive expression in tumour B cells. The TME consisted predominantly of CD163 (+) M2 TAMs and CD8 (+) TILs. Most TAMs expressed PDL1 and most TILs expressed PD1. The density of TAMs and TILs did not associate with outcome. We showed that expression of PD1 on TILs and PDL1 on TAMs, but not the expression of PDL1 on tumour B cells was correlated with better prognosis. These findings support a significant role of TME composition and PD1/PDL1 crosstalk in PCNS-DLBCL pathogenesis and bring new insights to the targeted therapy of this aggressive lymphoma.

The immune landscape of chondrosarcoma reveals an immunosuppressive environment in the dedifferentiated subtypes and exposes CSFR1+ macrophages as a promising therapeutic target

Survival rate for Chondrosarcoma (CHS) is at a standstill, more effective treatments are urgently needed. Consequently, a better understanding of CHS biology and its immune environment is crucial to identify new prognostic factors and therapeutic targets. Here, we exhaustively describe the immune landscape of conventional and dedifferentiated CHS. Using IHC and molecular analyses (RT-qPCR), we mapped the expression of immune cell markers (CD3, CD8, CD68, CD163) and immune checkpoints (ICPs) from a cohort of 27 conventional and 49 dedifferentiated CHS. The impact of the density of tumor-infiltrating lymphocytes (TILs), tumor-associated macrophages (TAMs) and immune checkpoints (ICPs) on clinical outcome were analyzed. We reveal that TAMs are the main immune population in CHS. Focusing on dedifferentiated CHS, we found that immune infiltrate composition is correlated with patient outcome, a high CD68+/CD8+ ratio being an independent poor prognostic factor (p < 0.01), and high CD68+ levels being associated with the presence of metastases at diagnosis (p < 0.05). Among the ICPs evaluated, CSF1R, B7H3, SIRPA, TIM3 and LAG3 were expressed at the mRNA level in both CHS subtypes. Furthermore, PDL1 expression was confirmed by IHC exclusively in dedifferentiated CHS (42.6% of the patients) and CSF1R was expressed by TAMs in 89.7% of dedifferentiated CHS (vs 62.9% in conventional). Our results show that the immune infiltrate of CHS is mainly composed of immunosuppressive actors favoring tumor progression. Our results indicate that dedifferentiated CHS could be eligible for anti-PDL1 therapy and more importantly immunomodulation through CSF1R + macrophages could be a promising therapeutic approach for both CHS subtypes.

Diffuse large B-cell lymphoma variants: an update

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

Involvement of extracellular vesicles in the macrophage-tumor cell communication in head and neck squamous cell carcinoma

Background

Exosomes are cell-derived vesicles that mediate cellular communication in health and multiple diseases, including cancer. However, its role in head and neck cancer has been poorly defined. Here, we investigated the relevance of exosomes in the signaling between larynx cancer cells and macrophages.

Methods

Exosomes from THP1 macrophages and BICR18 cells (a larynx squamous cell carcinoma cell line) were purified and their role in the cancer cell migration, macrophage phenotype and immunosuppressive activity was evaluated. The activation of STAT3 signal transduction in macrophages in response to exosomes obtained from cancer cells was also evaluated.

Results

Macrophages foster the cancer cell migration and this effect is mediated by exosome signaling. On the other hand, exosomes also induce the expression of IL-10 in macrophages and PD-L1 in cancer cells, thus resulting in the promotion of an immunosuppressive environment. Moreover, we observed that the effects induced in cancer cells are mediated by the exosome-depending activation of STAT-3 signal transduction pathway.

Conclusions

Our study indicates that exosomes released by both macrophages and cancer cells plays a critical role in tumor progression in larynx cancer and might be a potential target for therapeutic intervention in head and neck cancer.

Beyond T Cells: Understanding the Role of PD-1/PD-L1 in Tumor-Associated Macrophages

Programmed cell death protein 1 (PD-1) and its ligand PD-L1 have attracted wide attention from researchers in the field of immunotherapy. PD-1/PD-L1 have been shown to exist in many types of cells in addition to T lymphocytes, and studies have accordingly extended from their suppressive effect on T cell activation and function to examining their role in other cells. In this review, we summarize recent research on PD-1/PD-L1 in macrophages, with the aim of furthering our understanding of PD-1/PD-L1 and their detailed roles in macrophages. This information may provide additional insights for researchers, enrich the basic theory of anti-PD-1/PD-L1 immunotherapy, and thus ultimately benefit more patients.

Expression of programmed cell death-ligand 1 in primary testicular diffuse large B cell lymphoma: A retrospective study

The present study evaluated programmed cell death-ligand 1 (PD-L1) expression in tumor cells and in the tumor microenvironment (TME) and its association with clinical data in primary testicular diffuse large B cell lymphoma (DLBCL). PD-L1 was determined by immunohistochemistry in 30 patients with primary testicular DLBCL and assessed for associations with clinical characteristics, progression-free survival (PFS) and overall survival (OS). The mean patient age was 62.2 years. Overall, 10 (33.3%) patients had advanced-stage (stage III/IV) disease and 14 (46.7%) patients had an International Prognostic Index (IPI) of ≥3. The median follow-up time following orchiectomy was 23.5 months. During this time, 10 (33.3%) patients experienced disease progression and 11 (36.7%) patients succumbed. PD-L1 expression in tumor cells and in the TME was detected in 20 (66.7%) and 13 (43.3%) patients, respectively. PD-L1 expression on tumor cells and in the TME was higher in those at an early stage compared with patients with an advanced stage of disease (P=0.045 and 0.017, respectively). In addition, PD-L1 expression in tumor cells was higher in patients with a low IPI compared with those with a high IPI (P=0.019). A Kaplan-Meier analysis identified no association of PD-L1 expression on tumor cells with PFS (P=0.763) or OS (P=0.531), or of PD-L1 expression in the TME with PFS (P=0.572) or OS (P=0.934). The present study demonstrated that PD-L1 expression in tumor cells and in the TME was higher in patients at an early stage of disease compared with those at an advanced stage, and that PD-L1 expression on tumor cells was higher in patients with a low IPI than in those with a high IPI. Furthermore, PD-L1 expression in tumor cells and in the TME was not associated with PFS or OS.

Intravenous but not intrathecal central nervous system-directed chemotherapy improves survival in patients with testicular diffuse large B-cell lymphoma

BACKGROUND

Testicular lymphoma is a rare malignancy affecting mainly elderly men, the majority representing diffuse large B-cell lymphoma (DLBCL). Its relapse rate is higher than that of nodal DLBCL, often affecting the central nervous system (CNS) with dismal prognosis.

PATIENTS AND METHODS

We searched for patients with testicular DLBCL (T-DLBCL) involvement from the pathology databases of Southern Finland University Hospitals and the Danish Lymphoma Registry. Clinical information was collected, and outcomes between treatment modalities were evaluated. Progression-free survival (PFS), disease-specific survival (DSS) and overall survival (OS) were assessed using Kaplan-Meier and Cox proportional hazards methods.

RESULTS

We identified 235 patients; of whom, 192 were treated with curative anthracycline-based chemotherapy. Full survival data were available for 189 patients. In univariate analysis, intravenous CNS-directed chemotherapy, and irradiation or orchiectomy of the contralateral testis translated into favourable PFS, DSS and OS, particularly among the elderly patients (each p ≤ 0.023). Intrathecal chemotherapy had no impact outcome. In multivariate analyses, the advantage of intravenous CNS-directed chemotherapy (hazard ration [HR] for OS, 0.419; 95% confidence interval [CI], 0.256-0.686; p = 0.001) and prophylactic treatment of contralateral testis (HR for OS, 0.514; 95% CI, 0.338-0.782; p = 0.002) was maintained. Rituximab improved survival only among high-risk patients (International Prognostic Index≥3, p = 0.019). The cumulative risk of CNS progression was 8.4% and did not differ between treatment modalities.

CONCLUSION

The results support the use of CNS-directed chemotherapy and prophylactic treatment of the contralateral testis in patients with T-DLBCL involvement. Survival benefit appears resulting from better control of systemic disease rather than prevention of CNS progression.

T-cell inflamed tumor microenvironment predicts favorable prognosis in primary testicular lymphoma

Primary testicular lymphoma is a rare lymphoid malignancy, most often, histologically, representing diffuse large B-cell lymphoma. The tumor microenvironment and limited immune surveillance have a major impact on diffuse large B-cell lymphoma pathogenesis and survival, but the impact on primary testicular lymphoma is unknown. Here, the purpose of the study was to characterize the tumor microenvironment in primary testicular lymphoma, and associate the findings with outcome. We profiled the expression of 730 immune response genes in 60 primary testicular lymphomas utilizing the Nanostring platform, and used multiplex immunohistochemistry to characterize the immune cell phenotypes in the tumor tissue. We identified a gene signature enriched for T-lymphocyte markers differentially expressed between the patients. Low expression of the signature predicted poor outcome independently of the International Prognostic Index (progression-free survival: HR=2.810, 95%CI: 1.228-6.431, P=0.014; overall survival: HR=3.267, 95%CI: 1.406-7.590, P=0.006). The T-lymphocyte signature was associated with outcome also in an independent diffuse large B-cell lymphoma cohort (n=96). Multiplex immunohistochemistry revealed that poor survival of primary testicular lymphoma patients correlated with low percentage of CD3⁺CD4⁺ and CD3⁺CD8⁺ tumor-infiltrating lymphocytes (P<0.001). Importantly, patients with a high T-cell inflamed tumor microenvironment had a better response to rituximab-based immunochemotherapy, as compared to other patients. Furthermore, loss of membrane-associated human-leukocyte antigen complexes was frequent and correlated with low T-cell infiltration. Our results demonstrate that a T-cell inflamed tumor microenvironment associates with favorable survival in primary testicular lymphoma. This further highlights the importance of immune escape as a mechanism of treatment failure.