CD98hc promotes drug resistance in extranodal natural killer/T cell lymphoma through tumor cell-derived small extracellular vesicles.

Extranodal natural killer/T cell lymphoma (ENKTL) shows a high rate of recurrence after chemoradiotherapy. Drug resistance can be mediated by the cargo of small extracellular vesicles (sEVs). Here, we show that high abundance of the transmembrane glycoprotein CD98hc in tumor cells and serum sEVs was associated with ENKTL progression and drug resistance. Mechanistically, PEGylated-asparaginase (PEG-asp) treatment, a common therapy against ENKTL, promoted the translocation of the transcription factor ATF4 to the nucleus, where it was stabilized by USP1 and subsequently increased CD98hc expression. CD98hc delivered in tumor cell-derived sEVs increased tumor cell proliferation and drug resistance in a cultured human NK lymphoma cell line, animal models, and samples from patients with refractory/relapse ENKTL. Moreover, inhibiting both USP1 and EV secretion synergistically enhanced the cytotoxicity of PEG-asp. These data suggest that targeting CD98hc in the treatment of ENKTL may be beneficial in overcoming drug resistance.

LMP1 enhances aerobic glycolysis in natural killer/T cell lymphoma.

Natural killer/T cell lymphoma (NKTCL) exhibits highly aggressive clinical behavior, and the outcomes for relapsed/refractory patients are still poor. Recently, the mechanism underlying the effect of Epstein-Barr virus (EBV) infection, which has not been fully defined in NKTCL, has attracted great attention. We explored how LMP1 promoted aerobic glycolysis via metabolic sequencing combined with mRNA sequencing and immunoprecipitation coupled to mass spectrometry. Experimental assays were used to determine the effects of LMP1 and its downstream pathway on the function and glucose metabolism of NKTCL cells. The correlations between LMP1 expression in patients and their clinical features, treatment response, and prognosis were analyzed. Results show that LMP1 enhances NKTCL cell proliferation in vitro and in vivo, inhibits apoptosis, and decreases gemcitabine sensitivity. In addition, LMP1 also enhances aerobic glycolysis in NKTCL cells, as indicated by increases in glucose uptake, lactate production, and extracellular acidification rate. Clinically, LMP1 expression is correlated with risk stratification, treatment response, and prognosis, and higher LMP1 expression indicates greater SUVmax for NKTCL patients. Mechanistically, LMP1 competitively binds to TRAF3 to promote cell proliferation and aerobic glycolysis by regulating the noncanonical NF-κB pathway. The application of an NF-κB pathway inhibitor or reactivation of the NF-κB pathway affects aerobic glycolysis and the biological function of NKTCL cells. In summary, this study is the first to describe and define in detail how LMP1 affects glucose metabolism in NKTCL and might provide a novel perspective for further treatment.

TET2 regulates extranodal NK/T cell lymphoma progression through regulation of DNA methylation.

The biological role of Ten-11 translocation 2 (TET2) and the conversion of 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC) in the development of extra-nodal natural killer/T-cell lymphoma (ENKTL) remains unclear. The level of 5mC and 5hmC was detected in 112 cases of ENKTL tissue specimens by immunohistochemical (IHC) staining. Subsequently, TET2 knockdown and the overexpression cell models were constructed in ENKTL cell lines. Biochemical analyses were used to assess proliferation, apoptosis, cell cycle and monoclonal formation in cells treated or untreated with L-Ascorbic acid sodium salt (LAASS). Dot-Blots were used to detect levels of genome 5mC and 5hmC. Additionally, the ILLUMINA 850k methylation chip was used to analyze the changes of TET2 regulatory genes. RNA-Seq was used to profile differentially expressed genes regulated by TET2. The global level of 5hmC was significantly decreased, while 5mC was highly expressed in ENKTL tissue. TET2 protein expression was negatively correlated with the ratio of 5mC/5hmC (p < 0.0001). The 5mC/5hmC status were related to the site of disease, clinical stage, PINK score and Ki-67 index, as well as the 5-year OS. TET2 knockdown prolonged the DNA synthesis period, increased the cloning ability of tumor cells, increased the level of 5mC and decreased the level of 5hmC in ENKTL cells. While overexpression of TET2 presented the opposite effect. Furthermore, treatment of ENKTL cells with LAASS significantly induced ENKTL cell apoptosis. These results suggest that TET2 plays an important role in ENKTL development via regulation of 5mC and 5hmC and may serve as a novel therapeutic target for ENKTL.

Clinicopathological analysis of immunohistochemical CD47 and signal-regulatory protein-α expression in Extranodal Natural killer/T-cell lymphoma.

BACKGROUND: The interaction between CD47 and signal-regulatory protein-alpha (SIRPα) inhibits phagocytosis, and their clinicopathological characteristics have been evaluated in various diseases. However, the significance of CD47 and SIRPα expression, as well as the combined effect, in Extranodal Natural killer/T-cell Lymphoma (ENKTL) remains uncertain. METHODS: In total, 76 newly diagnosed ENKTL patients (mean age 49.9 years, 73.7% male) were included in this study. CD47 and SIRPα expression were examined by immunohistochemistry. Survival analyses were conducted through Kaplan-Meier curves and the Cox regression model. RESULTS: Seventy-one (93.4%) cases were categorized as the CD47 positive group and 59 (77.6%) cases were categorized as the SIRPα positive group. CD47-negative cases had more advanced-stage illness (P = 0.001), while SIRPα-positive cases showed significantly lower levels of high-density lipoprotein (P < 0.001). In univariable analysis, CD47, SIRPα expression, and their combination were significantly associated with prognosis (P < 0.05). In multivariable analysis, only positive SIRPα expression remained significantly associated with superior overall survival (Hazard ratio [HR] 0.446; 95% confidence interval [CI] 0.207-0.963; P = 0.004). Furthermore, SIRPα expression could re-stratify the survival of patients in ECOG (< 2), advanced CA stage, PINK (HR), CD38-positive, PD1-positive, and CD30-positive groups. CONCLUSIONS: SIRPα status was a potential independent prognostic factor for ENKTL. The prognostic significance of CD47 expression and the interaction between CD47 and SIRPα in ENKTL need further investigation.

METTL3 regulates M6A methylation-modified EBV-pri-miR-BART3-3p to promote NK/T cell lymphoma growth.

OBJECTIVE: N6-methyladenosine (M6A) is the most prevalent epigenetic alteration. Methyltransferase-like 3 (METTL3) is a key player in the control of M6A modification. Methyltransferase promote the processing of mature miRNA in an M6A-dependent manner, thereby participating in disease occurrence and development. However, the regulatory mechanism of M6A in NK/T cell lymphoma (NKTCL) remains unclear. PATIENTS AND METHODS: We determined the expression of METTL3 and its correlation with clinicopathological features using qRT-PCR and immunohistochemistry. We evaluated the effects of METTL3 on NKTCL cells using dot blot assay, CCK8 assay and subcutaneous xenograft experiment. We then applied M6A sequencing combined with gene expression omnibus data to screen candidate targets of METTL3. Finally, we investigated the regulatory mechanism of METTL3 in NKTCL by methylated RNA immunoprecipitation and RNA immunoprecipitation (RIP) assays. RESULTS: We demonstrated that METTL3 was highly expressed in NKTCL cells and tissues and indicated poor prognosis. The METTL3 expression was associated with NKTCL survival. Functionally, METTL3 promoted the proliferation capability of NKTCL cells in vitro and in vivo. Furthermore, EBV-miR-BART3-3p was identified as the downstream effector of METTL3, and silencing EBV-miR-BART3-3p inhibited the proliferation of NKTCL. Finally, we confirmed that PLCG2 as a target gene of EBVmiR-BART3-3p by relative assays. CONCLUSIONS: We identified that METTL3 is significantly up-regulated in NKTCL and promotes NKTCL development. M6A modification contributes to the progression of NKTCL via the METTL3/EBV-miR-BART3-3p/PLCG2 axis. Our study is the first to report that M6A methylation has a critical role in NKTCL oncogenesis, and could be a potential target for NKTCL treatment.

Increased coexpression of PD-L1 and IDO1 is associated with poor overall survival in patients with NK/T-cell lymphoma.

Immunotherapy with programmed cell death 1 ligand 1 (PD-L1) blockade was effective in patients with NK/T-cell lymphoma. In addition to PD-L1, indoleamine 2,3-dioxygenase-1 (IDO1) is one of the most promising immunotherapeutic targets. High proportions of PD-L1 and IDO1 proteins were observed by immunohistochemistry (IHC) from 230 newly diagnosed patients with NK/T lymphoma with tissue samples from three cancer centers and were associated with poor overall survival (OS) in patients with NK/T lymphoma. Importantly, the coexpression of PD-L1 and IDO1 was related to poor OS and short restricted mean survival time in patients with NK/T lymphoma and was an independent prognostic factor in the training cohorts, and which was also validated in 58 NK/T lymphoma patients (GSE90597). Moreover, a nomogram model constructed with PD-L1 and IDO1 expression together with age could provide concise and precise predictions of OS rates and median survival time. The high-risk group in the nomogram model had a positive correlation with CD4 + T-cell infiltration in the validation cohort, as did the immunosuppressive factor level. Therefore, high PD-L1 and IDO1 expression was associated with poor OS in patients with NK/T lymphoma. PD-L1 and IDO1 might be potential targets for future immune checkpoint blockade (ICB) therapy for NK/T lymphoma.

Comprehensive Genetic Profiling Reveals Frequent Alterations of Driver Genes on the X Chromosome in Extranodal NK/T-cell Lymphoma.

Extranodal NK/T-cell lymphoma (ENKTCL) is an Epstein-Barr virus (EBV)-related neoplasm with male dominance and a poor prognosis. A better understanding of the genetic alterations and their functional roles in ENKTCL could help improve patient stratification and treatments. In this study, we performed a comprehensive genetic analysis of 178 ENKTCL cases to delineate the landscape of mutations, copy number alterations (CNA), and structural variations, identifying 34 driver genes including six previously unappreciated ones, namely, HLA-B, HLA-C, ROBO1, CD58, POT1, and MAP2K1. Among them, CD274 (24%) was the most frequently altered, followed by TP53 (20%), CDKN2A (19%), ARID1A (15%), HLA-A (15%), BCOR (14%), and MSN (14%). Chromosome X losses were the most common arm-level CNAs in females (∼40%), and alterations of four X-linked driver genes (MSN, BCOR, DDX3X, and KDM6A) were more frequent in males and females harboring chromosome X losses. Among X-linked drivers, MSN was the most recurrently altered, and its expression was lost in approximately one-third of cases using immunohistochemical analysis. Functional studies of human cell lines showed that MSN disruption promoted cell proliferation and NF-κB activation. Moreover, MSN inactivation increased sensitivity to NF-κB inhibition in vitro and in vivo. In addition, recurrent deletions were observed at the origin of replication in the EBV genome (6%). Finally, by integrating the 34 drivers and 19 significant arm-level CNAs, nonnegative matrix factorization and consensus clustering identified two molecular groups with different genetic features and prognoses irrespective of clinical prognostic factors. Together, these findings could help improve diagnostic and therapeutic strategies in ENKTCL. Significance: Integrative genetic analyses and functional studies in extranodal NK/T-cell lymphoma identify frequent disruptions of X-linked drivers, reveal prognostic molecular subgroups, and uncover recurrent MSN alterations that confer sensitivity to NF-κB inhibition.

MYC overexpression in natural killer cell lymphoma: prognostic and therapeutic implications.

The current clinical management of extranodal natural killer (NK)/T-cell lymphoma (ENKTL) primarily depends on conventional chemotherapy and radiotherapy, underscoring the need for innovative therapeutic strategies. This study explores the clinical significance and therapeutic implication of c-MYC (MYC) in ENKTL. Initially, we identified MYC protein overexpression in approximately 75% of cases within a large cohort of 111 patients. MYC overexpression was strongly correlated with lymphoma cell proliferation and poor clinical outcomes. Intriguingly, integrating MYC expression into the prognostic index of NK cells lymphoma with Epstein-Barr virus (PINK-E) prognostic model significantly enhanced its predictive power. Subsequently, we implemented MYC knockdown in NK malignancy cell lines with MYC overexpression, resulting in significant viability reduction. RNA sequencing used to determine MYC function revealed a high overlap with canonical MYC-regulated genes and enrichment in metabolism and cell cycle regulation. Integrative analysis of the RNA-sequencing data upon MYC knockdown with gene expression profiles of primary ENKTL cases identified a subset of genes closely associated with MYC overexpression. Among these, CDK4 emerged as a potential therapeutic target, and its inhibition not only abrogated MYC function but also decreased MYC expression in NK malignancy cells. Furthermore, the clinical-grade CDK4/6 inhibitor palbociclib exhibited a potent anti-tumor effect in xenograft mouse models, especially when combined with gemcitabine. In summary, our study firmly establishes MYC as an oncogene with prognostic significance in ENKTL and highlights CDK4 inhibition as a promising therapeutic strategy for treating ENKTL with MYC overexpression.

Clinicopathologic features and survival outcomes of CD30 expression in extranodal natural killer/T-cell lymphoma.

OBJECTIVES: Previous studies have been inconsistent concerning the association between the prognostic value of CD30 expression and extranodal natural killer/T-cell lymphoma (ENKTL). METHODS: CD30 expression in 82 patients with newly diagnosed ENKTL (mean age, 50 years; 73.2% male) was assessed by immunohistochemistry on paraffin-embedded sections. The level of CD30 expression was categorized into negative (0%, no staining) and positive groups. RESULTS: Sixty-seven cases exhibited positive CD30 expression, and the main between-group difference was the Chinese Southwest Oncology Group and Asia Lymphoma Study Group (CA) ENKTL stage and Eastern Cooperative Oncology Group (ECOG) performance status. The cutoff point for CD30 expression was 40% by restricted cubic splines analysis. The overall survival of patients with high expression (>40%) was statistically superior to negative (0%) and low-expression groups. A positive correlation was observed between CD30 and Epstein-Barr virus-encoded small RNA status (r = 0.305). Multivariable analysis suggested that positive CD30 expression (hazard ratio, 0.420 [95% CI, 0.193-0.914]; P = .029) and CA advanced stage (hazard ratio, 2.844 [95% CI, 1.371-5.896]; P = .005) were independent prognostic factors for ENKTL. CONCLUSIONS: Positive CD30 expression was a favorable prognostic factor for ENKTL, and CD30 expression could restratify the survival of patients in clinical subgroups.

Pitfalls in diagnosing a case of extranodal NK/T-cell lymphoma with CD20 aberrant expression and IGH gene rearrangement.

Extranodal NK/T-cell lymphoma (ENKTL) is a subtype of non-Hodgkin lymphoma mainly derived from NK cells and, uncommonly, T-cells. A diagnostic challenge is presented when an atypical phenotype and gene rearrangement are encountered. Herein, we report a case of ENKTL with CD20 expression and IGH gene rearrangement, which is extremely rare. A 57-year-old female patient was seen in 2021 due to a nodule on her left leg and simultaneously impaired eyesight for 6 months. Skin biopsy and immunohistochemistry were performed. The lymphoid cells were positive for CD3, CD56, granzyme B, and TIA-1, partially positive for CD2, and mildly positive for CD20. In situ hybridization for Epstein-Barr virus was positive. Molecular studies revealed immunoglobulin heavy chain (IGH) gene rearrangement, while no T-cell receptor gene rearrangement was detected. The positron emission tomography scan showed that the lymphoma affected bilateral adrenal glands, pelvic cavity, peritoneal cavity, small intestine, skin, and subcutis of the bilateral lower extremities of the patient. Her disease progressed despite eight cycles of chemotherapy and radiation therapy. The importance of this case lies in the atypical phenotype and IGH gene rearrangements, necessitating comprehensive interpretation of clinicopathological data.

Diagnostic value of IL-22, IL-23, and IL-17 for NK/T cell lymphoma.

NK/T cell lymphoma (NKTCL) is a common blood cancer, and early diagnosis of this disease is crucial. This study is aimed to investigate the roles of IL-17, IL-22 as well as IL-23 for the diagnosis of NKTCL. Sixty-five patients with NKTCL were included and the blood samples were collected, and sixty healthy objectives served as the controls. Serums of the patients and controls were collected. The expression levels of IL-17, IL-22, and IL-23 were examined using enzyme-linked immunosorbent (ELISA) assay. The receiver operator characteristic (ROC) curve was drawn for determining the potential diagnostic value of these cytokines. The serum levels of IL-17 (156.0 ± 67.75 pg/mL), IL-22 (39.98 ± 23.88 pg/mL), and IL-23 (43.05 ± 25.69 pg/mL) were all markedly increased in NKTCL patients (P<0.001); ROC analysis showed the serum level of IL-17, IL-22, and IL-23 could serve as the potential diagnostic biomarker for NKTCL with high sensitivity and specificity. The AUC of IL-17 was 0.9487 (95% confidence interval (CI), 0.9052 to 0.9922). Area under the curve (AUC) of IL-22 was 0.7321 (95% CI, 0.6449 to 0.8192). The AUC of IL-23 was 0.7885 (95% CI, 0.7070 to 0.8699). Our data indicated that IL-17, IL-22, and IL-23 were all increased in NKTCL and may function as potential diagnostic biomarkers for NKTCL.

T-cell dysfunction in natural killer/T-cell lymphoma.

Natural killer/T-cell lymphoma (NKTCL) is an incurable aggressive T-cell lymphoma closely correlated with Epstein‒Barr virus (EBV) infection. Chronic and consistent viral infection induces T-cell exhaustion. Herein, we describe T-cell dysfunction in NKTCL patients for the first time. Peripheral blood mononuclear cells (PBMCs) from age-matched healthy donors (HDs) and NKTCL patients were collected, and lymphocyte distributions, multiple surface inhibitory receptors (IRs), effector cytokine production and cell proliferation were determined by flow cytometry. PBMCs from HDs were cocultured with NKTCL cell lines to verify the clinical findings. IR expression was further assessed in NKTCL tumor biopsies using multiplex immunohistochemistry (mIHC). NKTCL patients have higher frequencies than HDs of inhibitory T regulatory cells (Tregs) and myeloid-derived suppressor cells (MDSCs). T-cell distribution also varies between NKTCL patients and HDs. T cells from NKTCL patients demonstrated higher expression levels of multiple IRs than HDs. Meanwhile, T-cell proliferation and interferon-γ production was significantly reduced in NKTCL patients. More importantly, the number of EBV-specific cytotoxic cells was lower in NTKCL patients, and these cells demonstrated upregulation of multiple IRs and secreted fewer effector cytokines. Interestingly, NKTCL cells caused normal PBMCs to acquire T-cell exhaustion phenotypes and induced generation of Tregs and MDSCs. In line with ex vivo finding, mIHC results showed that CD8+ T cells from NKTCL tumor biopsies expressed much higher level of IRs compared with reactive lymphoid hyperplasia individuals. The immune microenvironment of NKTCL patients exhibited T-cell dysfunction and accumulation of inhibitory cell components, which may contribute to impaired antitumor immunity.

Prognostic value of prognostic nutritional index on extranodal natural killer/T-cell lymphoma patients: A multicenter propensity score matched analysis of 1022 cases in Huaihai Lymphoma Working Group.

Prognostic nutritional index (PNI), comprised of serum albumin level and lymphocyte count, is associated with the prognosis of several malignant diseases, while the prognostic value of PNI in extranodal natural killer/T cell lymphoma, nasal type (ENKTL) remains unclear. This retrospective multicenter study aimed to investigate the value of PNI in predicting the prognosis of newly diagnosed ENKTL patients by using propensity score matched analysis (PSM). A total of 1022 newly diagnosed ENKTL patients were retrieved from Huaihai Lymphoma Working Group and clinicopathological variables were collected. MaxStat analysis was used to calculate the optimal cut-off points of PNI and other continuous variables. The median age at diagnosis was 47 years and 69.4% were males, with the 5-year OS of 71.7%. According to the MaxStat analysis, 41 was the optimal cut-off point for PNI. The Pseudo R2 before matching was 0.250, and it decreased to less than 0.019 after matching. Confounding factors of the two groups were well balanced after PSM. Multivariable analysis revealed that PNI, Korean Prognostic Index (KPI), eastern cooperative oncology group performance status (ECOG PS), the prognostic index of natural killer lymphoma (PINK) and hemoglobin were independent prognostic factors for ENKTL. The results of subgroup analysis demonstrated that patients with low PNI could predict worse prognosis and re-stratify patients in ECOG PS ≥ 2, EBER-positive, the International Prognostic Index (IPI) (HIR + HR), and PINK (HR) groups. PNI combined with IPI, PINK and KPI could improve the prediction efficiency. In conclusion, PNI could accurately stratify the prognosis of ENKTL by PSM analysis and patients with low PNI had poorer prognosis.

Comprehensive Analysis and Summary of the Value of Immunophenotypes of Mature NK Cell Tumors for Differential Diagnosis, Treatment, and Prognosis.

Background: Few studies have been performed to comprehensively analyze and summarize the immunophenotype and differential diagnosis of mature NK cell tumors, and there is often overlap between tumorigenic and reactive NK cell phenotypes. Furthermore, the impact of different phenotypes on patient prognosis has rarely been reported. Methods: The degree of expression of extracellular and intracellular markers of NK cells in each group was compared by FCM, and the differences in expression of various markers among different disease groups and their impact on prognosis have been analyzed and summarized. Results: Compared with normal NK cells, tumor cells of ANKL and ENKTL had characteristics of being more activated and progressive with larger FSC, in contrast to NK-CLPD and RNKL. Differential diagnoses with RNKL, ANKL, and ENKTL have broader FCM clues. In contrast, the phenotypes of NK-CLPD and RNKL are not significantly different, and consistent phenotypic abnormalities require ongoing monitoring to confirm malignant clones. The sensitivity of differentiating malignant NK cells from reactive NK cells by KIRs alone was poor. The clustering results showed that CD5, CD16, CD56, CD57, CD94, CD45RA, CD45RO, HLA-DR, KIRs, Granzyme B, Perforin and Ki-67 were differentially distributed in the expression of three NK cell tumors and reactive NK cell hyperplasia, so a comprehensive judgment using a wide range of antibody combinations is required in disease staging diagnosis. The tumor cell loads in BM and PB were also compared, and there was a clear correlation between the two. Moreover, the sensitivity of PB for monitoring tumor cells was up to 87.10%, suggesting that PB could be used as an alternative to BM for the diagnosis and screening of NK cell tumors. Analysis of the phenotypic impact of ENKTL patients on prognosis showed that those with CD7 and CD45RO expression had a poor prognosis, while those with positive KIRs had a better prognosis. Conclusion: This study systematically characterized the FCM of mature NK cell tumors, emphasizing the importance and clinical value of accurate immunophenotyping in diagnosing, classifying, determining prognosis, and guiding treatment of the disease.

IL-10 contributes to gemcitabine resistance in extranodal NK/T-cell lymphoma cells via ABCC4.

Background Chemotherapy resistance is a main reason for treatment failure in extranodal NK/T-cell lymphoma (ENKTL). Interleukin-10 (IL-10) is closely related to the occurrence and prognosis of ENKTL. We intended to study the role and molecular mechanism of IL-10 in ENKTL resistance. Methods Fifty serum samples were collected from patients with a histologically proven diagnosis of ENKTL. Fifty healthy volunteers were enrolled as a control group. The level of serum IL-10 was detected by ELISA. The NK/T-cell lymphoma cell lines YT and NK-92 were divided into the control group (untreated), IL-10 group (treated with IL-10), IL-10 + GEM group (treated with IL-10 and gemcitabine simultaneously) and GEM group (treated with gemcitabine). A CCK8 assay and flow cytometry were employed to detect the effects of IL-10 on each group. Western blotting was applied to detect the expression of ABC membrane transporter family proteins and signaling pathway proteins in each group. Results Serum IL-10 levels were higher in ENKTL patients as well asin patients with ineffective treatment. The IC50 value for gemcitabine in YT and NK-92 cells increased significantly in the presence of IL-10. The effects of gemcitabine resulting in cell killing, cell cycle arrest, and apoptosis promotion were also weakened by IL-10. The expression of ABCC4, STAT1, p-STAT1, Tyk2 and p-Tyk2 was significantly increased by IL-10. Conclusion Our results indicate that IL-10 contributes to the resistance of ENKTL cells via ABCC4 and that IL-10 regulates the JAK/STAT signaling pathway in YT and NK-92 cells.

T and NK cell lymphoma cell lines do not rely on ZAP-70 for survival.

B-cell receptor (BCR) signalling is critical for the survival of B-cell lymphomas and is a therapeutic target of drugs such as Ibrutinib. However, the role of T-cell receptor (TCR) signalling in the survival of T/Natural Killer (NK) lymphomas is not clear. ZAP-70 (zeta associated protein-70) is a cytoplasmic tyrosine kinase with a critical role in T-cell receptor (TCR) signalling. It has also been shown to play a role in normal NK cell signalling and activation. High ZAP-70 expression has been detected by immunohistochemistry in peripheral T cell lymphoma (PTCL) and NK cell lymphomas (NKTCL). We therefore, studied the role of TCR pathways in mediating the proliferation and survival of these malignancies through ZAP-70 signalling. ZAP-70 protein was highly expressed in T cell lymphoma cell lines (JURKAT and KARPAS-299) and NKTCL cell lines (KHYG-1, HANK-1, NK-YS, SNK-1 and SNK-6), but not in multiple B-cell lymphoma cell lines. siRNA depletion of ZAP-70 suppressed the phosphorylation of ZAP-70 substrates, SLP76, LAT and p38MAPK, but did not affect cell viability or induce apoptosis in these cell lines. Similarly, while stable overexpression of ZAP-70 mediates increased phosphorylation of target substrates in the TCR pathway, it does not promote increased survival or growth of NKTCL cell lines. The epidermal growth factor receptor (EGFR) inhibitor Gefitinib, which has off-target activity against ZAP-70, also did not show any differential cell kill between ZAP-70 overexpressing (OE) or knockdown (KD) cell lines. Whole transcriptome RNA sequencing highlighted that there was very minimal differential gene expression in three different T/NK cell lines induced by ZAP-70 KD. Importantly, ZAP-70 KD did not significantly enrich for any downstream TCR related genes and pathways. Altogether, this suggests that high expression and constitutive signalling of ZAP-70 in T/NK lymphoma is not critical for cell survival or downstream TCR-mediated signalling and gene expression. ZAP-70 therefore may not be a suitable therapeutic target in T/NK cell malignancies.

The expression and clinical significance of programmed cell death receptor 1 and its ligand in tumor tissues of patients with extranodal nasal NK/T cell lymphoma.

Appropriate biomarkers may help distinguish the biological behavior of different types of lymphoma and their response to traditional chemotherapy. Extranodal natural killer/T-cell lymphoma (ENKTL) and diffuse large B-cell lymphoma (DLBCL) belong to different subtypes of non-Hodgkin's lymphoma, the biological behavior and prognosis of them are very different, programmed cell death receptor 1 (PD-1) and its ligand (PD-L1) have been investigated in these two types of diseases. However, few studies addressed the difference of PD-1/PD-L1 levels between ENKTL and DLBCL, in order to find out the difference and related clinical application value, the clinical data and tumor tissue paraffin sections of 24 newly diagnosed ENKTL patients and 42 newly diagnosed diffuse large B-cell lymphoma (DLBCL) were collected. PD-1/PD-L1 levels in tumor tissues were detected by immunohistochemical staining. The relationship between the PD-1/PD-L1 levels and clinical data of patients with ENKTL patients was analyzed. Both patient groups showed PD-1 level in tumor tissue of ENKTL patients was significantly lower than that of DLBCL patients (P < 0.05), while the PD-L1 level in tumor tissues of ENKTL patients was not different from DLBCL (P < 0.05). In addition, the ENKTL patients with B symptoms, elevated lactate dehydrogenase (LDH) levels and decreased hemoglobin (HGB) concentrations had lower level of PD-1 in tumor tissue. PD-L1 level in tumor tissues, the LDH level, Epstein-Barr genome (EBV-DNA) copy and Ki-67 index may affect the outcomes of ENKTL patients (P < 0.05), but they were not independent factors. PD-L1 levels in tumor tissues has clinical significance in ENKTL patients, which suggested that the PD-1/PD-L1 signal pathway may be involved in the immune escape of ENKTL and play different roles in different lymphoma subtypes.

Clinicopathologic and Genetic Features of Primary T-cell Lymphomas of the Central Nervous System: An Analysis of 11 Cases Using Targeted Gene Sequencing.

Primary central nervous system lymphoma (PCNSL) of peripheral T-cell lineage (T-PCNSL) is rare, and its genetic and clinicopathologic features remain unclear. Here, we present 11 cases of T-PCNSL in immunocompetent individuals from a single institute, focusing on their genetic alterations. Seven cases were subject to targeted panel sequencing covering 120 lymphoma-related genes. Nine of the eleven cases were classified as peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS), of which one was of γδT-cell lineage. There was one case of anaplastic lymphoma kinase-positive anaplastic large cell lymphoma and another of extranodal natural killer (NK)/T-cell lymphoma (ENKTL) of αßT-cell lineage. The male to female ratio was 7 : 4 and the age ranged from 3 to 75 years (median, 61 y). Most patients presented with neurological deficits (n=10) and showed multifocal lesions (n=9) and deep brain structure involvement (n=9). Tumor cells were mostly small-to-medium, and T-cell monoclonality was detected in all nine evaluated cases. PTCL-NOS was CD4-positive (n=4), CD8-positive (n=3), mixed CD4-positive and CD8-positive (n=1), or CD4/CD8-double-negative (n=1, γδT-cell type). Cytotoxic molecule expression was observed in 4 (67%) of the 6 evaluated cases. Pathogenic alterations were found in 4 patients: one PTCL-NOS case had a frameshift mutation in KMT2C, another PTCL-NOS case harbored a truncating mutation in TET2, and another (γδT-cell-PTCL-NOS) harbored NRAS G12S and JAK3 M511I mutations, and homozygous deletions of CDKN2A and CDKN2B. The ENKTL (αßT-cell lineage) case harbored mutations in genes ARID1B, FAS, TP53, BCOR, KMT2C, POT1, and PRDM1. In conclusion, most of the T-PCNSL were PTCL-NOS, but sporadic cases of other subtypes including γδT-cell lymphoma, anaplastic lymphoma kinase-positive anaplastic large cell lymphoma, and ENKTL were also encountered. Immunophenotypic analysis, clonality test, and targeted gene sequencing along with clinicoradiologic evaluation, may be helpful for establishing the diagnosis of T-PCNSL. Moreover, this study demonstrates genetic alterations with potential diagnostic and therapeutic utility in T-PCNSL.

The Acetyltransferase KAT5 Inhibitor NU 9056 Promotes Apoptosis and Inhibits JAK2/STAT3 Pathway in Extranodal NK/T Cell Lymphoma.

BACKGROUND: Extranodal natural killer/T cell lymphoma (ENKTL) is an aggressive malignant non- Hodgkin's lymphoma (NHL) with a poor prognosis. Therefore, novel therapeutic biomarkers and agents must be identified for the same. KAT5 inhibitor, NU 9056, is a small molecule that can inhibit cellular proliferation; however, its role in ENKTL has not been studied. OBJECTIVE: The present study investigated the effect of NU 9056 in ENKTL cells and explored the possible molecular mechanism for its antitumour effect. METHODS: The role of NU 9056 in ENKTL cells was investigated through the Cell Counting Kit-8 assay, flow cytometry, Western blot, and real-time quantitative polymerase chain reaction assay. RESULTS: NU 9056 inhibited ENKTL cell proliferation and induced G2/M phase arrest. NU 9056 also induced apoptosis by upregulating DR4, DR5, and caspase 8 expressions. Additionally, NU 9056 increased the expression of Bax, Bid, and cytochrome C and decreased the expression of Bcl-2, Mcl-1, and XIAP. Furthermore, NU 9056 activated endoplasmic reticulum (ER) stress and inhibited the JAK2/STAT3 signalling pathway. The p38 mitogen-activated protein kinase (MAPK) signalling pathway was also activated by NU 9056, and the ERK signalling pathway was suppressed in natural killer/T cell lymphoma cells. CONCLUSION: NU 9056 inhibited cell proliferation, arrested cell cycle in the G2/M phase, and induced apoptosis through the stimulation of ER stress, thus inhibiting the JAK2/STAT3 signalling pathway and regulating MAPK pathways in ENKTL cells.

Primary breast CD20-positive extranodal NK/T cell lymphoma with stomach involvement: a case report and literature review.

BACKGROUND: We present a unique case of primary breast CD20-positive extranodal NK/T cell lymphoma with stomach involvement in a young Chinese female patient. CASE PRESENTATION: The patient presented with a mass in her right breast that rapidly increased in size over approximately 2 months. Upper gastrointestinal endoscopy showed a giant serpentine ulcer in the stomach. Biopsy was performed, and microscopic inspection revealed that the fibrous tissue was diffusely involved by medium to large abnormal lymphocytes. The cytoplasm was low to moderate. The tumor cells had irregular nuclei and inconspicuous nucleoli. The lymphoid cells were strongly immunoreactive to CD20, CD3, CD4, CD56, TIA-1, EBER, and Ki-67 (90%). Epstein-Barr virus genomes were also found in tumor cells by in situ hybridization. A whole-body positron emission tomography (PET)-CT scan revealed intense FDG uptake in the right breast and greater curvature of the stomach. Monoclonal rearrangements of the T cell receptor (TCR-γ) and immunoglobulin heavy chain (IgH) were identified by genetic analysis. Whole-genome next-generation sequencing was performed, and up to 12 gene mutations, including a frameshift mutation in exon 4 of the BCOR (G97Rfs*87; 44.3%) gene and a base substitution mutation (Q61H 17.6%) in exon 3 of the KRAS gene, were detected. Kyoto Encyclopedia of Genes and Genomes pathway analyses were performed using the database for annotation, visualization, and integrated discovery, which showed that rare primary breast CD20-positive extranodal NK/T cell lymphoma had a unique genetic background compared with diffuse large B cell lymphoma and extranodal NK/T cell lymphoma without CD20 expression. The patient received four cycles of the modified SMILE regimen. The second whole-body PET-CT scan revealed that the right breast mass was significantly smaller than before; additionally, FDG uptake in the stomach wall disappeared. CONCLUSIONS: Systemic examination, extensive immunohistochemistry, and molecular profiling are essential for an accurate diagnosis. More similar cases are required to clarify the biological pathways and even the potential molecular mechanisms of rare lymphomas, which may help direct further treatment.