High-resolution genome-wide analysis identified recurrent genetic alterations in NK/T-cell lymphoma, nasal type, which are associated with disease progression

Somatic genomic imbalances in 'tumour-free' surgical margins of oral cancer

Up to 30% of oral squamous cell carcinoma (OSCC) patients develop local recurrence and distant metastasis. The molecular status of histologically cancer-free tumour margins could be a critical factor in predicting tumour behaviour. The aim of this study was to detect somatic genomic imbalances in OSCC with emphasis on the surgical margins. DNA was isolated from tumour tissues, margin tissues, and blood samples (used as control) obtained from 11 OSCC patients, and genome-wide array comparative genomic hybridization was performed. Imbalances were present in both tumours and margins, although, as expected, they were more prevalent in tumours (duplications, P = 0.0002; deletions, P = 0.0001). Duplications were more frequent than deletions in both tumours and margins, but without statistical significance. Fifteen imbalances in tumour tissues were recurrent and all of them were duplications. Four of these were found both in tumours and margins and involved chromosomes 1q, 8p, Xp, Yp, and Yq. Four imbalances were recurrent in margin tissue and all of them were duplications (autosomes 8 and 17 and both sex chromosomes). Histologically 'cancer-free' margins hide genomic alterations consistent with unexplained OSCC recurrences. Establishing the molecular status of the margins could improve outcome prediction.

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.

ADAM3A copy number gains occur in a subset of conjunctival squamous cell carcinoma and its high grade precursors

Conjunctival squamous cell carcinoma (cSCC) and its precursors are among the most frequent ocular surface neoplasms worldwide. Copy gain of 8p11.22 and ADAM3A overexpression have been recently identified in invasive cSCC. We sought to study copy number gains using fluorescent in situ hybridization (FISH) in cSCC and the spectrum of precursor lesions. A total of 54 cases conjunctival squamous intraepithelial neoplasia (CIN), carcinoma in situ (CIS), or cSCC were studied using FISH with an ADAM3A (8p11 locus) probe and a chromosome 8 (Chr 8) centromere reference probe. Eighty one percent (44/54) of the cases presented in men and 19% (10/54) in women. The age at presentation ranged from 12 to 94 years (mean 65.5 years). Severe CIN was diagnosed in 45% (24/54) of the cases, followed by CIS in 31% (17/54), moderate CIN in 15% (8/54), invasive cSCC in 7% (4/54), and mild CIN in 2% (1/54). Nine (of 54) (17%) cases harbored ADAM3A or Chr 8 gains, with one of these cases demonstrating high level amplification. All ADAM3A alterations were restricted to high-grade lesions, including 2/17 (12%) cCIS, 1/4 (24%) cSCC, 5/24 (20%) severe CIN and 1/8 (12%) moderate CIN. Monosomy 8 was detected in 2 (4%) cases. No ADAM3A alterations were detected in non-neoplastic controls. Gains of ADAM3A/chromosome 8 occur in a subset of cSCC and its precursors. Alterations were present in high-grade lesions, sparing non-neoplastic conjunctiva and absent in tested controls. Thus, the specificity of this alteration as a biomarker for ocular SCC deserves further study.

Molecular pathogenic pathways in extranodal NK/T cell lymphoma

Extranodal NK/T cell lymphoma, nasal type (ENKTL) is an aggressive malignancy with a dismal prognosis. Although L-asparaginase-based chemotherapy has resulted in improved response rates, relapse occurs in up to 50% of patients with disseminated disease. There is hence an urgent need for effective targeted therapy, especially for patients with relapsed or refractory disease. Novel insights gleaned from high-throughput molecular and genomic profiling studies in recent years have contributed significantly to the understanding of the molecular biology of ENKTL, which exemplifies many of the hallmarks of cancer. Deregulated pro-proliferative signaling pathways, such as the Janus-associated kinase/signal transducer and activator of transcription (JAK/STAT), platelet-derived growth factor (PDGF), Aurora kinase, MYC, and NF-κB, have been identified as potential therapeutic targets. The discovery of the non-canonical function of EZH2 as a pro-proliferative transcriptional co-activator has shed further light on the pathogenesis of ENKTL. Loss of key tumor suppressor genes located on chromosome 6q21 also plays an important role. The best-studied examples include PR domain zinc finger protein 1(PRDM1), protein tyrosine phosphatase kappa (PTPRK), and FOXO3. Promoter hypermethylation has been shown to result in the downregulation of other tumor suppressor genes in ENKTL, which may be potentially targeted through hypomethylating agents. Deregulation of apoptosis through p53 mutations and upregulation of the anti-apoptotic protein, survivin, may provide a further growth advantage to this tumor. A deranged DNA damage response as a result of the aberration of ataxia telangiectasia-related (ATR) kinases can lead to significant genomic instability and may contribute to chemoresistance of ENKTL. Recently, immune evasion has emerged as a critical pathway for survival in ENKTL and may be a consequence of HLA dysregulation or STAT3-driven upregulation of programmed cell death ligand 1 (PD-L1). Immunotherapy via inhibition of programmed cell death 1 (PD-1)/PD-L1 checkpoint signaling holds great promise as a novel therapeutic option. In this review, we present an overview of the key molecular and pathogenic pathways in ENKTL, organized using the framework of the "hallmarks of cancer" as described by Hanahan and Weinberg, with a focus on those with the greatest translational potential.

The Genomics and Molecular Biology of Natural Killer/T-Cell Lymphoma: Opportunities for Translation

Extranodal NK/T-cell lymphoma, nasal type (ENKTL), is an aggressive malignancy with a poor prognosis. While the introduction of L-asparaginase in the treatment of this disease has significantly improved the prognosis, the outcome of patients relapsing after asparaginase-based chemotherapy, which occurs in up to 50% of patients with disseminated disease, remains dismal. There is hence an urgent need for effective targeted therapy especially in the relapsed/refractory setting. Gene expression profiling studies have provided new perspectives on the molecular biology, ontogeny and classification of ENKTL and further identified dysregulated signaling pathways such as Janus associated kinase (/Signal Transducer and activation of transcription (JAK/STAT), Platelet derived growth factor (PDGF), Aurora Kinase and NF-κB, which are under evaluation as therapeutic targets. Copy number analyses have highlighted potential tumor suppressor genes such as PR Domain Zinc Finger Protein 1 (PRDM1) and protein tyrosine phosphatase kappa (PTPRK) while next generation sequencing studies have identified recurrently mutated genes in pro-survival and anti-apoptotic pathways. The discovery of epigenetic dysregulation and aberrant microRNA activity has broadened our understanding of the biology of ENKTL. Importantly, immunotherapy via Programmed Cell Death -1 (PD-1) and Programmed Cell Death Ligand1 (PD-L1) checkpoint signaling inhibition is emerging as an attractive therapeutic strategy in ENKTL. Herein, we present an overview of the molecular biology and genomic landscape of ENKTL with a focus on the most promising translational opportunities.

Malignant lymphoma of the conjunctiva

Conjunctival lymphomas constitute 25% of all ocular adnexal lymphomas. The majority are B-cell non-Hodgkin lymphomas (NHLs) (98%), whereas conjunctival T-cell NHLs are rare (2%). The most frequent subtype of conjunctival B-cell lymphoma is extranodal marginal zone lymphoma (EMZL; 81%), followed by follicular lymphoma (8%), diffuse large B-cell lymphoma (3%), and mantle cell lymphoma (3%). Extranodal marginal zone lymphoma occurs slightly more often in women and, along with follicular lymphoma, presents late in the seventh decade of life, whereas diffuse large B-cell lymphoma and especially mantle cell lymphoma have a predilection for the male gender and typically present in the eighth decade. Extranodal marginal zone lymphoma and follicular lymphoma present most frequently in the forniceal and bulbar conjunctiva. Conjunctival diffuse large B-cell lymphoma, mantle cell lymphoma and T-cell NHLs are characterized by a short duration of symptoms before the first ophthalmologic consultation. External beam radiotherapy is the treatment of choice for extranodal marginal zone lymphoma and follicular lymphoma, whereas diffuse large B-cell lymphoma, mantle cell lymphoma, and T-cell NHLs are mainly treated with chemotherapy. Conjunctival T-cell NHLs are associated with a particularly poor prognosis, with 50% of patients having progression or recurrence during a 1-year follow-up period.