Recurrent GNAQ mutation encoding T96S in natural killer/T cell lymphoma

Analysis of mutation profiles in extranodal NK/T-cell lymphoma: clinical and prognostic correlations

The molecular pathogenesis of extranodal NK/T-cell lymphoma (NKTCL) remains obscured despite the next-generation sequencing (NGS) studies explored on ever larger cohorts in the last decade. We addressed the highly variable mutation frequencies reported among previous studies with comprehensive amplicon coverage and enhanced sequencing depth to achieve higher genomic resolution for novel genetic discovery and comparative mutational profiling of the oncogenesis of NKTCL. Targeted exome sequencing was conducted to interrogate 415 cancer-related genes in a cohort of 36 patients with NKTCL, and a total of 548 single nucleotide variants (SNVs) and 600 Copy number variances (CNVs) were identified. Recurrent amplification of the MCL1 (67%) and PIM1 (56%) genes was detected in a dominant majority of patients in our cohort. Functional mapping of genetic aberrations revealed that an enrichment of mutations in the JAK-STAT signaling pathway, including the cytokine receptor LIFR (copy number loss) upstream of JAK3, STAT3 (activating SNVs), and downstream effectors of MYC, PIM1 and MCL1 (copy number gains). RNA in situ hybridization showed the significant consistence of MCL1 RNA level and copy number of MCL1 gene. We further correlated molecular and clinical parameters with overall survival (OS) of these patients. When correlations were analyzed by univariate followed by multivariate modelling, only copy number loss of LIFR gene and stage (III-IV) were independent prognostic factors of reduced OS. Our findings identified that novel loss of LIFR gene significantly correlated with the adverse clinical outcome of NKTCL patients and provided therapeutic opportunities for this disease through manipulating LIFR.

Contribution of the Epstein-Barr virus to the oncogenesis of mature T-cell lymphoproliferative neoplasms

EBV is a lymphotropic virus, member of the Herpesviridae family that asymptomatically infects more than 90% of the human population, establishing a latent infection in memory B cells. EBV exhibits complex survival and persistence dynamics, replicating its genome through the proliferation of infected B cells or production of the lytic virions. Many studies have documented the infection of T/NK cells by EBV in healthy individuals during and after primary infection. This feature has been confirmed in humanized mouse models. Together these results have challenged the hypothesis that the infection of T/NK cells per se by EBV could be a triggering event for lymphomagenesis. Extranodal NK/T-cell lymphoma (ENKTCL) and Epstein-Barr virus (EBV)-positive nodal T- and NK-cell lymphoma (NKTCL) are two EBV-associated lymphomas of T/NK cells. These two lymphomas display different clinical, histological and molecular features. However, they share two intriguing characteristics: the association with EBV and a geographical prevalence in East Asia and Latin America. In this review we will discuss the genetic characteristics of EBV in order to understand the possible role of this virus in the oncogenesis of ENKTCL and NKTCL. In addition, the main immunohistological, molecular, cytogenetic and epigenetic differences between ENKTCL and NKTCL will be discussed, as well as EBV differences in latency patterns and other viral molecular characteristics.

Whole-Exome Sequencing and cfDNA Analysis Uncover Genetic Determinants of Melanoma Therapy Response in a Real-World Setting

Although several studies have explored the molecular landscape of metastatic melanoma, the genetic determinants of therapy resistance are still largely unknown. Here, we aimed to determine the contribution of whole-exome sequencing and circulating free DNA (cfDNA) analysis in predicting response to therapy in a consecutive real-world cohort of 36 patients, undergoing fresh tissue biopsy and followed during treatment. Although the underpowered sample size limited statistical analysis, samples from non-responders had higher copy number variations and mutations in melanoma driver genes compared to responders in the BRAF V600+ subset. In the BRAF V600- subset, Tumor Mutational Burden (TMB) was twice that in responders vs. non-responders. Genomic layout revealed commonly known and novel potential intrinsic/acquired resistance driver gene variants. Among these, RAC1, FBXW7, GNAQ mutations, and BRAF/PTEN amplification/deletion were present in 42% and 67% of patients, respectively. Both Loss of Heterozygosity (LOH) load and tumor ploidy were inversely associated with TMB. In immunotherapy-treated patients, samples from responders showed higher TMB and lower LOH and were more frequently diploid compared to non-responders. Secondary germline testing and cfDNA analysis proved their efficacy in finding germline predisposing variants carriers (8.3%) and following dynamic changes during treatment as a surrogate of tissue biopsy, respectively.

Romidepsin-induced durable remission for relapsed nodal peripheral T-cell lymphoma with T follicular helper phenotype after allogeneic hematopoietic cell transplantation

Patients with recurrent peripheral T-cell lymphoma (PTCL) after allogeneic hematopoietic cell transplantation (HCT) have dismal outcomes. Nodal PTCL with the T follicular helper phenotype (PTCL-TFH) is uniquely sensitive to histone deacetylase inhibitors compared to non-TFH phenotypes. We report the case of a 19-year-old man who experienced recurrence of PTCL-TFH shortly after allogeneic HCT and subsequently achieved durable remission with romidepsin. Before HCT, the patient had refractory disease after CHOP and ESHAP chemotherapies but achieved a partial response after two cycles of romidepsin as salvage treatment. HLA-haploidentical peripheral blood stem cell transplantation was performed using conditioning with fludarabine 180 mg/sqm, melphalan 80 mg/sqm, and total body irradiation 2 Gy, and graft-versus-host disease (GVHD) prophylaxis with post-transplantation cyclophosphamide. One month after HCT, disease progression was observed in the lung. Romidepsin was readministered every 2 weeks at a reduced dose of 12 mg/sqm. After two cycles of romidepsin, the patient achieved a complete metabolic response without severe GVHD or other non-hematological toxicities. Romidepsin was discontinued after seven treatment cycles due to prolonged lymphopenia. The patient remains in complete remission 30 months after the last dose of romidepsin. Our experience suggests that romidepsin could be safely administered soon after allogeneic transplantation.

GNAQ mutations drive port wine birthmark-associated Sturge-Weber syndrome: A review of pathobiology, therapies, and current models

Port-wine birthmarks (PWBs) are caused by somatic, mosaic mutations in the G protein guanine nucleotide binding protein alpha subunit q (GNAQ) and are characterized by the formation of dilated, dysfunctional blood vessels in the dermis, eyes, and/or brain. Cutaneous PWBs can be treated by current dermatologic therapy, like laser intervention, to lighten the lesions and diminish nodules that occur in the lesion. Involvement of the eyes and/or brain can result in serious complications and this variation is termed Sturge-Weber syndrome (SWS). Some of the biggest hurdles preventing development of new therapeutics are unanswered questions regarding disease biology and lack of models for drug screening. In this review, we discuss the current understanding of GNAQ signaling, the standard of care for patients, overlap with other GNAQ-associated or phenotypically similar diseases, as well as deficiencies in current in vivo and in vitro vascular malformation models.

Integrated driver mutations profile of chinese gastrointestinal-natural killer/T-cell lymphoma

Background

One of the most common nasal external sites in extranodal Natural Killer/T-cell lymphoma (NKTCL) is in the gastrointestinal (GI) system. Despite this, reports on gastrointestinal-Natural Killer/T-cell lymphoma (GI-NKTCL) are very few. To obtain a better understanding of this manifestation of NKTCL, we conducted a retrospective study on GI-NKTCL to analyze its clinical features, genomic changes and immune infiltration.

Methods

We retrospectively collected patients diagnosed with GI-NKTCL in the Sixth Affiliated Hospital of Sun Yat-sen University from 2010 to 2020. From this cohort we obtained mutation data via whole exome sequencing.

Results

Genomic analysis from 15 patients with GI-NKTCL showed that the most common driving mutations were ARID1B(14%, 2/15), ERBB3(14%, 2/15), POT1(14%, 2/15), and TP53(14%, 2/15). In addition, we found the most common gene mutation in patients with GI-NKTCL to be RETSAT(29%, 4/15) and SNRNP70(21%, 3/15), and the most common hallmark pathway mutations to be G2M checkpoint pathway (10/15, 66.7%), E2F targets (8/15, 53.3%), estrogen response late (7/15, 46.7%), estrogen response early (7/15, 46.7%), apoptosis (7/15, 46.7%) and TNFA signaling via NFKB (7/15, 46.7%). In the ICIs-Miao cohort, SNRNP7-wild-type (WT) melanoma patients had significantly prolonged overall survival (OS) time compared with SNRNP7 mutant type (MT) melanoma patients. In the TCGA-UCEC cohort, the patients with RETSAT-MT or SNRNP7-MT had significantly increased expression of immune checkpoint molecules and upregulation of inflammatory immune cells.

Conclusions

In this study, we explored GI-NKTCL by means of genomic analysis, and identified the most common mutant genes (RETSAT and SNRNP70), pathway mutations (G2M checkpoint and E2F targets) in GI-NKTCL patients. Also, we explored the association between the common mutant genes and immune infiltration. Our aim is that our exploration of these genomic changes will aid in the discovery of new biomarkers and therapeutic targets for those with GI-NKTCL, and finally provide a theoretical basis for improving the treatment and prognosis of patients with GI-NKTCL.

Overarching roles of diacylglycerol signaling in cancer development and antitumor immunity

Diacylglycerol (DAG) is a lipid second messenger that is generated in response to extracellular stimuli and channels intracellular signals that affect mammalian cell proliferation, survival, and motility. DAG exerts a myriad of biological functions through protein kinase C (PKC) and other effectors, such as protein kinase D (PKD) isozymes and small GTPase-regulating proteins (such as RasGRPs). Imbalances in the fine-tuned homeostasis between DAG generation by phospholipase C (PLC) enzymes and termination by DAG kinases (DGKs), as well as dysregulation in the activity or abundance of DAG effectors, have been widely associated with tumor initiation, progression, and metastasis. DAG is also a key orchestrator of T cell function and thus plays a major role in tumor immunosurveillance. In addition, DAG pathways shape the tumor ecosystem by arbitrating the complex, dynamic interaction between cancer cells and the immune landscape, hence representing powerful modifiers of immune checkpoint and adoptive T cell-directed immunotherapy. Exploiting the wide spectrum of DAG signals from an integrated perspective could underscore meaningful advances in targeted cancer therapy.

The GNAQ T96S mutation abrogates the ability of wild-type GNAQ to induce apoptosis by phosphorylating ANXA2 in natural killer/T cell lymphoma

Our previous study identified Annexin A2 (ANXA2) as a Gaq-interacting partner in natural killer/T cell lymphoma (NKTCL) cells transfected with the GNAQ T96S mutation vector by immunoprecipitation and mass spectrometry; however, the detailed molecular mechanisms by which GNAQ T96S might regulate ANXA2 remain to be defined in NKTCL. Herein, we found that the GNAQ T96S mutation significantly promotes the phosphorylation of ANXA2 at the Y24 site, whereas phosphorylation of ANXA2 abolishes the ability of wild-type GNAQ to trigger cell apoptosis. Further investigation revealed that a GNAQ T96S peptide inhibitor induced apoptosis by competing with ANXA2 binding to GNAQ T96S in NKTCL cells. In vivo animal experiments demonstrated that a GNAQ T96S peptide inhibitor suppresses the growth of NKTCL cells carrying the GNAQ T96S mutation. Our current data suggest a role for GNAQ T96S/Src/ANXA2 in mediating the apoptosis of NKTCL cells, and the GNAQ T96S peptide may be a promising agent for therapy in NKTCL patients.

Exonic variants in multiple myeloma patients associated with relapsed/ refractory and response to bortezomib regimens

Novel treatment in multiple myeloma represented by proteasome inhibitors, immunomodulatory drugs and monoclonal antibodies have produced a deep response. However, relapses are possible, and all classes of drugs are refractory to patients. Next-generation sequencing has improved our understanding of the multiple myeloma genome related to drug resistance and has discovered many genomic variants. Therefore, this study was conducted to investigate new variants associated with drug resistance in MM patients who relapsed and refractory to bortezomib regimen and daratumumab treatment using next-generation sequencing for whole-exome sequencing. Peripheral blood samples were collected in EDTA tubes from six patients; four were in relapsed and refractory to bortezomib regimens and daratumumab; two patients responded to bortezomib regimens. Whole-exome sequencing was performed by the MGI-DNBSEQ-G400 instrument. We identified 21 variants in multiple myeloma patients. Seventeen variants were found in relapsed and refractory multiple myeloma in 11 genes (GNAQ, PMS1, CREB1, NSUNS2, PIK3CG, ROS1, PMS2, FIT4, KDM5A, STK11 and ZFHX3). And four variants were identified in two patients with response to bortezomib regimens in 4 genes (RAF1, CREB1, ZFHX3 and INSR). We have observed several genetic variants in many genes that may have been associated with the poor prognosis and poor response to treatment in these patients. These values should be further confirmed in large sample studies using the RNA-seq technique to identify genome expression.

An Insight into GPCR and G-Proteins as Cancer Drivers

G-protein-coupled receptors (GPCRs) are the largest family of cell surface signaling receptors known to play a crucial role in various physiological functions, including tumor growth and metastasis. Various molecules such as hormones, lipids, peptides, and neurotransmitters activate GPCRs that enable the coupling of these receptors to highly specialized transducer proteins, called G-proteins, and initiate multiple signaling pathways. Integration of these intricate networks of signaling cascades leads to numerous biochemical responses involved in diverse pathophysiological activities, including cancer development. While several studies indicate the role of GPCRs in controlling various aspects of cancer progression such as tumor growth, invasion, migration, survival, and metastasis through its aberrant overexpression, mutations, or increased release of agonists, the explicit mechanisms of the involvement of GPCRs in cancer progression is still puzzling. This review provides an insight into the various responses mediated by GPCRs in the development of cancers, the molecular mechanisms involved and the novel pharmacological approaches currently preferred for the treatment of cancer. Thus, these findings extend the knowledge of GPCRs in cancer cells and help in the identification of therapeutics for cancer patients.

Preclinical Application of Conditional Reprogramming Culture System for Laryngeal and Hypopharyngeal Carcinoma

Management of laryngeal and hypopharyngeal squamous cell carcinoma (LHSCC) remains highly challenging due to highly variable therapeutic responses. By establishing an in vitro model for LHSCC based on conditional reprogramming (CR), a cell-culture technique, we aim to investigate its potential value on personalized cancer therapies. Herein, a panel of 28 human LHSCC CR cells were established from 50 tumor tissues using the CR method. They retained tumorigenic potential upon xenotransplantation and recapitulated molecular characteristics of LHSCC. Differential responses to anticancer drugs and radiotherapy were detected in vitro. CR cells could be transformed to xenograft and organoid, and they shared comparable drug responses. The clinical drug responses were consistent with in vitro drug responses. Collectively, the patient-derived CR cell model could promisingly be utilized in clinical decision-making and assisted in the selection of personalized therapies for LHSCC.

Coexisting and Second Primary Cancers in Patients with Uveal Melanoma: A 10-Year Nationwide Database Analysis

Uveal melanoma is the most common intraocular tumor in adults. Metastatic disease occurs in about 30% of patients, for which there is currently no effective treatment. More than half of patients are long-term survivors, and it is well established that cancer survivors are prone to developing second primary cancers. In this study, we analyzed 10 years’ worth of data from the nationwide database to determine the rates of coexisting malignancies and second primary cancers associated with uveal melanoma. The mean annual incidence of uveal melanoma was 1.1 per million. Approximately 43% of patients had coexisting cancers. The most common coexisting cancer was lung cancer (10%) followed by liver cancer (6%) and non-Hodgkin lymphoma (6%). In patients whose first cancer in their lifetime was uveal melanoma, the 10-year cumulative incidence of second primary cancers was 22% (95% confidence interval, 9–31%). The age- and sex-adjusted standard incidence rates was 3.61 (95% confidence interval, 2.61–4.86). The most common second primary cancers were lung cancer and hepatocellular carcinoma, followed by prostate, thyroid, pancreatic, and ovarian cancers. Age was the only factor associated with second primary cancer development. Our findings will be helpful in providing counseling for cancer screening in uveal melanoma patients.

Suppression of latent transforming growth factor-β (TGF-β)-binding protein 1 (LTBP1) inhibits natural killer/ T cell lymphoma progression by inactivating the TGF-β/Smad and p38MAPK pathways

BACKGROUND

Natural killer/T cell lymphoma (NKTCL) is a distinct subtype of Non-Hodgkin's lymphoma with highly aggressive clinical behavior. We aim to investigate the function of Latent transforming growth factor β binding protein 1 (LTBP1) and transforming growth factor beta1 (TGF-β1) and complex molecular pathogenesis of this disease.

METHODS

NKTCL patients and reactive lymph nodes patients were recruited in this study. The expression of LTBP1 and TGF-β1 was examined using qRT-PCR, Western blot, IHC and ELISA analyses in biopsied tissues and serum from participants and NKTCL cell lines. Cell proliferation was determined using CFSE. Cell cycle and apoptosis were evaluated using flow cytometric analyses. The expression of Ki-67, CDK4 and cyclinD1 proteins was measured using Western blot analyses. The roles of LTBP-1/TGF-β1 in EMT program were determined by measuring E-cadherin, N-cadherin and Vimentin using Western blot analyses. The effects of LTBP-1 and TGF-β1 on tumor progression in vivo were determined by animal experiments.

RESULTS

LTBP-1 and TGF-β1 levels were elevated in NKTCL tissues and serum. The expression of LTBP-1 was positively correlated with the expression of TGF-β1 in NKTCL tissues. LTBP-1 was overexpressed in NKTCL cells. Knockdown of LTBP-1 suppressed cell proliferation and cell cycle progression, induced cell apoptosis, and suppressed EMT program in NKTCL cells. These effects of LTBP-1 knockdown were attenuated after TGF-β1 stimulation. Knockdown of LTBP-1 inhibited NKTCL tumor weight and volume in vivo. Also, stimulation of TGF-β1 attenuated the suppressive effects on tumor growth from sh-LTBP-1. Silencing of LTBP-1 lowered cellular TGF-β1, phosphorylated-Smad2, phosphorlyatd-Smad3, and phosphorylated-p38 and the suppressive effects were reversed after stimulation of TGF-β1.

CONCLUSION

Our findings suggested that inhibition of LTBP-1/TGF-β1 suppressed the malignant phenotypes of NKTCL cells and tumor growth via inactivating the canonical TGF-β/Smad signaling and p38^MAPK signaling.

G Protein-Coupled receptors and heterotrimeric G proteins as cancer drivers

G protein-coupled receptors (GPCRs) and heterotrimeric G proteins play central roles in a diverse array of cellular processes. As such, dysregulation of GPCRs and their coupled heterotrimeric G proteins can dramatically alter the signalling landscape and functional state of a cell. Consistent with their fundamental physiological functions, GPCRs and their effector heterotrimeric G proteins are implicated in some of the most prevalent human diseases, including a complex disease such as cancer that causes significant morbidity and mortality worldwide. GPCR/G protein-mediated signalling impacts oncogenesis at multiple levels by regulating tumour angiogenesis, immune evasion, metastasis, and drug resistance. Here, we summarize the growing body of research on GPCRs and their effector heterotrimeric G proteins as drivers of cancer initiation and progression, and as emerging antitumoural therapeutic targets.

Virus-Driven Carcinogenesis

Cancer arises from the accumulation of genetic and epigenetic alterations. Even in the era of precision oncology, carcinogens contributing to neoplastic process are still an important focus of research. Comprehensive genomic analyses have revealed various combinations of base substitutions, referred to as the mutational signatures, in cancer. Each mutational signature is believed to arise from specific DNA damage and repair processes, including carcinogens. However, as a type of carcinogen, tumor viruses increase the cancer risk by alternative mechanisms, including insertional mutagenesis, viral oncogenes, and immunosuppression. In this review, we summarize virus-driven carcinogenesis to provide a framework for the control of malignant cell proliferation. We first provide a brief overview of oncogenic viruses and describe their implication in virus-related tumors. Next, we describe tumor viruses (HPV, Human papilloma virus; HBV, Hepatitis B virus; HCV, Hepatitis C virus; EBV, Epstein-Barr virus; Kaposi sarcoma herpesvirus; MCV, Merkel cell polyoma virus; HTLV-1, Human T-cell lymphotropic virus, type-1) and tumor virus-related cancers. Lastly, we introduce emerging tumor virus candidates, human cytomegalovirus (CMV), human herpesvirus-6 (HHV-6) and adeno-associated virus-2 (AAV-2). We expect this review to be a hub in a complex network of data for virus-associated carcinogenesis.

Survival trends for extranodal NK/T-cell lymphoma, nasal type from different anatomical sites: a population-based study

Background

Extranodal natural killer/T-cell lymphoma (NKTCL), nasal type mostly involves the upper aerodigestive tract (UAT). NKTCLs derived from the UAT are referred to as nasal NKTCLs, while those without UAT involvement are referred to as extra-nasal NKTCLs. In this study, we aimed to investigate the outcomes and survival trends of NKTCLs from different anatomical sites.

Methods

Data from the US Surveillance, Epidemiology, and End Results (SEER) database on NKTCL (diagnosed between 1987 and 2016) were retrospectively analyzed.

Results

A total of 714 patients with NKTCL were included. The median overall survival (OS) and cancer-specific survival (CSS) were 36 and 57 months, respectively. For the entire cohort, the OS was improved from era 1 to era 2 with marginal significance (P=0.0595), however, no improvement was shown in CSS. For nasal NKTCLs, the OS of patients from era 2 was significantly improved compared to that of patients from era 1 (P=0.0244). The OS was significantly improved in non-cavity nasal NKTCLs (P=0.031) but not in nasal cavity NKTCLs (P=0.2982). Significant improvements in OS (P=0.0025) and CSS (P=0.0176) were found in stage I/II non-cavity nasal NKTCLs. For patients with extra-nasal NKTCLs, no difference was found in survival outcomes between the 2 eras.

Conclusions

We have demonstrated that the outcomes of non-cavity nasal NKTCLs, especially those in stage I/II, have improved in the new era, while the outcomes of nasal cavity NKTCLs and extra-nasal NKTCLs have not improved. Our study highlights the heterogeneity in clinical outcomes and biology among NKTCLs from different sites. More studies are warranted to define the optimal treatments for patients with NKTCLs.

The GNAQ T96S Mutation Affects Cell Signaling and Enhances the Oncogenic Properties of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC), the most common malignant tumor in the liver, grows and metastasizes rapidly. Despite advances in treatment modalities, the five-year survival rate of HCC remains less than 30%. We sought genetic mutations that may affect the oncogenic properties of HCC, using The Cancer Genome Atlas (TCGA) data analysis. We found that the GNAQ T96S mutation (threonine 96 to serine alteration of the Gαq protein) was present in 12 out of 373 HCC patients (3.2%). To examine the effect of the GNAQ T96S mutation on HCC, we transfected the SK-Hep-1 cell line with the wild-type or the mutant GNAQ T96S expression vector. Transfection with the wild-type GNAQ expression vector enhanced anchorage-independent growth, migration, and the MAPK pathways in the SK-Hep-1 cells compared to control vector transfection. Moreover, cell proliferation, anchorage-independent growth, migration, and the MAPK pathways were further enhanced in the SK-Hep-1 cells transfected with the GNAQ T96S expression vector compared to the wild-type GNAQ-transfected cells. In silico structural analysis shows that the substitution of the GNAQ amino acid threonine 96 with a serine may destabilize the interaction between the regulator of G protein signaling (RGS) protein and GNAQ. This may reduce the inhibitory effect of RGS on GNAQ signaling, enhancing the GNAQ signaling pathway. Single nucleotide polymorphism (SNP) genotyping analysis for Korean HCC patients shows that the GNAQ T96S mutation was found in only one of the 456 patients (0.22%). Our data suggest that the GNAQ T96S hotspot mutation may play an oncogenic role in HCC by potentiating the GNAQ signal transduction pathway.

EBV and the Pathogenesis of NK/T Cell Lymphoma

Epstein-Barr virus (EBV) is a ubiquitous gamma herpes virus with tropism for B cells. EBV is linked to the pathogenesis of B cell, T cell and NK cell lymphoproliferations, with extranodal NK/T cell lymphoma, nasal type (ENKTCL) being the prototype of an EBV-driven lymphoma. ENKTCL is an aggressive neoplasm, particularly widespread in East Asia and the native population of Latin America, which suggests a strong genetic predisposition. The link between ENKTCL and different populations has been partially explored. EBV genome sequencing analysis recognized two types of strains and identified variants of the latent membrane protein 1 (LMP1), which revealed different oncogenic potential. In general, most ENKTCL patients carry EBV type A with LMP1 wild type, although the LMP1 variant with a 30 base pair deletion is also common, especially in the EBV type B, where it is necessary for oncogenic transformation. Contemporary high-throughput mutational analyses have discovered recurrent gene mutations leading to activation of the JAK-STAT pathway, and mutations in other genes such as BCOR, DDX3X and TP53. The genomic landscape in ENKTCL highlights mechanisms of lymphomagenesis, such as immune response evasion, secondary to alterations in signaling pathways or epigenetics that directly or indirectly interfere with oncogenes or tumor suppressor genes. This overview discusses the most important findings of EBV pathogenesis and genetics in ENKTCL.

sATP‑binding cassette subfamily G member 2 enhances the multidrug resistance properties of human nasal natural killer/T cell lymphoma side population cells

Extranodal natural killer (NK)/T cell lymphoma, nasal type (ENKL) is a rare type of non-Hodgkin's lymphoma that is associated with limited effective treatment options and unfavorable survival rate, which is partly the result of multidrug resistance (MDR). The presence of side population (SP) cells-SNK-6/ADM-SP (SSP) cells has been previously used to explore mechanisms of drug resistance. ATP-binding cassette subfamily G member 2 (ABCG2) is a gene involved in MDR and is closely associated with SPs. However, the function of ABCG2 in SSP cells is unclear. The present study verified the high expression of ABCG2 in SSP cells. The IC₅₀ values of doxorubicin, cytarabine, cisplatin, gemcitabine and l-asparaginase were tested to evaluate drug sensitivity in SSP cells with different levels of ABCG2 expression. ABCG2 was identified as a gene promoting in MDR. ABCG2 upregulated cell proliferation, increased clonogenicity, increased invasive ability and decreased apoptosis, in vivo and in vitro, when cells were treated with gemcitabine. To conclude, ABCG2 enhanced MDR and increased the typical biological characteristics associated with cancer cells in SP cells. With further investigation of the ABCG2 gene could have the potential to reverse MDR in ENKL.

CDC27 Promotes Tumor Progression and Affects PD-L1 Expression in T-Cell Lymphoblastic Lymphoma

T-lymphoblastic lymphoma (T-LBL) is a rare hematological malignancy with highly aggressive, unique clinical manifestations, and poor prognosis. Cell division cycle 27 (CDC27) was previously reported to be a significant subunit of the anaphase-promoting complex/cyclosome. However, the specific functions and relevant mechanisms of CDC27 in T-LBL remain unknown. Through immunohistochemistry staining, we identified that CDC27 was overexpressed in T-LBL tissues and related to tumor progression and poor survival. Functional experiments demonstrated that CDC27 promoted proliferation in vivo and in vitro. Further experiment suggested the role of CDC27 in facilitating G1/S transition and promoting the expression of Cyclin D1 and CDK4. Then the effect of CDC27 in inhibiting apoptosis was also identified. Furthermore, we found a positive correlation between the expression of CDC27 and Programmed death ligand-1 (PD-L1) by immunohistochemistry staining. The interaction between CDC27 and PD-L1 was also proved by western blot, luciferase gene reporter assay and immunofluorescence. Taken together, our results showed that CDC27 contributes to T-LBL progression and there is a positive correlation between PD-L1 and CDC27, which offers novel perspectives for future studies on targeting CDC27 in T-LBL.

Diffuse bone and soft tissue angiomatosis with GNAQ mutation

We describe a unique case of skeletal and extraskeletal angiomatosis complicated by Kasabach-Merritt syndrome. The patient was a 3-year-old boy, who presented with involvement of both femurs and left tibia, as well as with soft tissue lesions of the left thigh. At birth, multiple hemangiomas of the soft tissues of the frontal and parietal scalp had been identified, together with a space-occupying lesion of the lung. Histologically, the skeletal and soft tissue lesions consisted of a proliferation of thin-walled, dilated blood vessels, with an endothelial lining devoid of atypia and exhibiting immunoreactivity for CD31 and CD34, while podoplanin and GLUT1 were negative. Whole exome sequencing performed on samples from the lesion of the femur, the tibia and the skin of the thigh, showed a GNAQ (c.286A>T:p.T96S) variant in all specimens, that was confirmed with digital droplet PCR. This case expands the clinical and pathologic spectrum of vascular proliferations showing similar molecular biology, characterized by GNAQ, GNA11 or GNA14 mutations.