Comparative methylome analysis in solid tumors reveals aberrant methylation at chromosome 6p in nasopharyngeal carcinoma

© 2015 The Authors. Cancer Medicine published by John Wiley & Sons Ltd. Altered patterns of DNA methylation are key features of cancer. Nasopharyngeal carcinoma (NPC) has the highest incidence in Southern China. Aberrant methylation at the promoter region of tumor suppressors is frequently reported in NPC; however, genome-wide methylation changes have not been comprehensively investigated. Therefore, we systematically analyzed methylome data in 25 primary NPC tumors and nontumor counterparts using a high-throughput approach with the Illumina HumanMethylation450 BeadChip. Comparatively, we examined the methylome data of 11 types of solid tumors collected by The Cancer Genome Atlas (TCGA). In NPC, the hypermethylation pattern was more dominant than hypomethylation and the majority of de novo methylated loci were within or close to CpG islands in tumors. The comparative methylome analysis reveals hypermethylation at chromosome 6p21.3 frequently occurred in NPC (false discovery rate; FDR=1.33 × 10 -9 ), but was less obvious in other types of solid tumors except for prostate and Epstein-Barr virus (EBV)-positive gastric cancer (FDR < 10 -3 ). Bisulfite pyrosequencing results further confirmed the aberrant methylation at 6p in an additional patient cohort. Evident enrichment of the repressive mark H3K27me3 and active mark H3K4me3 derived from human embryonic stem cells were found at these regions, indicating both DNA methylation and histone modification function together, leading to epigenetic deregulation in NPC. Our study highlights the importance of epigenetic deregulation in NPC. Polycomb Complex 2 (PRC2), responsible for H3K27 trimethylation, is a promising therapeutic target. A key genomic region on 6p with aberrant methylation was identified. This region contains several important genes having potential use as biomarkers for NPC detection.published_or_final_versio

Adverse effects if TERT-CLPTM1L and double-strand breaks repair contribute to risk for NPC

Epidemiology - Poster Presentations - Proffered Abstracts - Poster Presentations - Molecular and Genetic Epidemiology of Lung, Head and Neck, and Gastrointestinal Cancers: abstract no. 4148This journal suppl. entitled: Proceedings: AACR Annual Meeting 2014; April 5-9, 2014 ...BACKGROUND AND AIMS: The genetic etiology of NPC and mechanisms for inherited susceptibility remain unclear. Only modest low-penetrance effects of cancer-predisposing common variant SNPs were previously identified in the few large-scale NPC association studies reported. Most NPC association studies focused on single or limited candidate genes with modest sample sizes. Systematic and comprehensive study designs for evaluation of higher order gene-gene interactions are scanty. A large-scale NPC case-control SNP association study was performed to examine the genetic risk factors for NPC development. In order to elucidate the ...postprin

NF-κB p65 Subunit Is Modulated by Latent Transforming Growth Factor-β Binding Protein 2 (LTBP2) in Nasopharyngeal Carcinoma HONE1 and HK1 Cells

NF-kappa B is a well-characterized transcription factor, widely known as a key player in tumor-derived inflammation and cancer development. Herein, we present the functional and molecular relevance of the canonical NF-kappa B p65 subunit in nasopharyngeal carcinoma (NPC). Loss-and gain-of-function approaches were utilized to reveal the functional characteristics of p65 in propagating tumor growth, tumor-associated angiogenesis, and epithelial-to-mesenchymal transition in NPC cells. Extracellular inflammatory stimuli are critical factors that trigger the NF-kappa B p65 signaling; hence, we investigated the components of the tumor microenvironment that might potentially influence the p65 signaling pathway. This led to the identification of an extracellular matrix (ECM) protein that was previously reported as a candidate tumor suppressor in NPC. Our studies on the Latent Transforming Growth Factor-beta Binding Protein 2 (LTBP2) protein provides substantial evidence that it can modulate the p65 transcriptional activity. Re-expression of LTBP2 elicits tumor suppressive effects that parallel the inactivation of p65 in NPC cells. LTBP2 was able to reduce phosphorylation of p65 at Serine 536, inhibit nuclear localization of active phosphorylated p65, and impair the p65 DNA-binding ability. This results in a consequential down-regulation of p65-related gene expression. Therefore, the data suggest that the overall up-regulation of p65 expression and the loss of this candidate ECM tumor suppressor are milestone events contributing to NPC development.published_or_final_versio

Hedgehog/notch-induced premature gliogenesis represents a new disease mechanism for Hirschsprung disease in mice and humans

Hirschsprung (HSCR) disease is a complex genetic disorder attributed to a failure of the enteric neural crest cells (ENCCs) to form ganglia in the hindgut. Hedgehog and Notch are implicated in mediating proliferation and differentiation of ENCCs. Nevertheless, how these signaling molecules may interact to mediate gut colonization by ENCCs and contribute to a primary etiology for HSCR are not known. Here, we report our pathway- based epistasis analysis of data generated by a genome-wide association study on HSCR disease, which indicates that specific genotype constellations of Patched (PTCH1) (which encodes a receptor for Hedgehog) and delta-like 3 (DLL3) (which encodes a receptor for Notch) SNPs confer higher risk to HSCR. Importantly, deletion of Ptch1 in mouse ENCCs induced robust Dll1 expression and activation of the Notch pathway, leading to premature gliogenesis and reduction of ENCC progenitors in mutant bowels. Dll1 integrated Hedgehog and Notch pathways to coordinate neuronal and glial cell differentiation during enteric nervous system development. In addition, Hedgehog-mediated gliogenesis was found to be highly conserved, such that Hedgehog was consistently able to promote gliogenesis of human neural crest-related precursors. Collectively, we defined PTCH1 and DLL3 as HSCR susceptibility genes and suggest that Hedgehog/Notch-induced premature gliogenesis may represent a new disease mechanism for HSCR.published_or_final_versio

Clinical spectrum of Exophiala infections and a novel Exophiala species, Exophiala hongkongensis

Poster PresentationBackground: Exophiala species are saprophytic fungi which have been isolated from environments rich in hydrocarbons or from hot, humid, and oligotrophic environments. These fungi are considered as dematiaceous moulds; and due to their phenotypic characteristics at the beginning of colony formation, they are also often referred to as ‘black yeasts’, a misnomer which sometimes may mislead the choice of antifungal agents. When the cultures mature, brown hyphae are formed bearing conidiogenous cells referred to as annellides, a typical characteristic of this fungal genus. Although Exophiala species are environmental fungi, they should not be disregarded as contaminants when they are isolated from clinical specimens. These fungi are causative agents of skin and subcutaneous tissue infections and of systemic infections, such as prosthetic valve endocarditis, dialysis-associated peritonitis, and disseminated infections, especially in immunocompromised patients. Unfortunately, Exophiala species can often only be identified to the genus level by phenotypic characterisation. Objectives: The aims of this study were to study the clinical spectrum of Exophiala infections in Queen Mary Hospital, Hong Kong by a polyphasic approach, and to characterise a potentially novel Exophiala species, Exophiala hongkongensis (ex-type strain HKU32T). Methods: All Exophiala strains characterised in this study were isolated from patients during a 15-year period (1998-2012) and were retrieved from the collection in the clinical microbiology laboratory at Queen Mary Hospital, Hong Kong. The strains were characterised phenotypically by microscopic examination of fungal structure using the agar block smear preparation method and phylogenetically using the internal transcribed spacer (ITS) region and Rpb1 gene. In addition, a unique strain, HKU32T, was further characterised phenotypically by scanning electron microscopy, enzyme activity test using the API-ZYM system, and growth tests on different temperatures and culture media. HKU32T was also further phylogenetically characterised using β-tubulin and β-actin genes. All the phylogenetic analyses were performed by the maximum likelihood method using MEGA 5.0.5. Results: Microscopic examination of the young cultures of all the 12 strains showed subspherical, budding, yeast-like cells. Sequencing of the ITS region and partial Rpb1 gene showed 11 of the 12 strains were known Exophiala species, including E. oligosperma [n = 3], E. jeanselmei [n = 2], E. lecanii-corni [n = 2], E. bergeri [n = 1], E. cancerae [n = 1], E. dermatitidis [n = 1], and E. xenobiotica [n = 1]). As for HKU32T, it displayed unique morphological features and was positive for eight enzymes in the API-ZYM test. Optimal growth was observed at 30°C on potato dextrose agar or at 24°C on cornmeal agar. HKU32T also occupied unique phylogenetic positions in all the phylogenetic analyses, with Exophiala nishimurae being the most closely related species. Clinical spectrum of Exophiala infections in Hong Kong included chronic skin infection, colonisation of gastrointestinal tract, continuous ambulatory peritoneal dialysis (CAPD) peritonitis, onychomycosis, pneumonia, tinea pedis, and wrist or finger nodule. Conclusion: Exophiala species could cause a wide range of infections and the most frequent species isolated from patients in Hong Kong was Exophiala oligosperma. Exophiala hongkongensis sp. nov. is proposed to describe the unique strain HKU32T

The Impact of the Oncotype DX Breast Cancer Assay on Treatment Decisions for Women With Estrogen Receptor-Positive, Node-Negative Breast Carcinoma in Hong Kong

Background The Oncotype DX Breast Cancer Assay is validated to assess risk of distant recurrence and likelihood of chemotherapy (CT) benefit in estrogen receptor-positive ESBC in various populations. In Hong Kong, > 80% of breast cancers are early stage breast cancer (ESBC) and > 60% of these women receive CT. This prospective study measured changes in CT type and recommendations, as well as physician impression of assay impact in a homogenous Chinese population. Methods Consecutive patients with estrogen receptor-positive, T1-3 N0-1mi M0 ESBC were offered enrollment. After surgery, physicians discussed treatment options with patients, then ordered the assay, then reassessed treatment recommendation considering assay results. Changes in treatment recommendation, CT utilization, physician confidence, and physician rating of influence on their treatment recommendations were measured. Results A total of 146 evaluable patients received pre- and post-testing treatment recommendations. CT recommendations (including changes in intensity of CT) were changed for 34 of 146 patients (23.3%; 95% confidence interval, 16.7%-31.0%); change in intensity occurred in 7 of 146 (4.8%). There were 27 changes in treatment recommendations of adding or removing CT altogether (18.5% change; 95% confidence interval, 12.6%-25.8%). CT recommendations decreased from 52.1% to 37.7%, a net absolute reduction of 14.4% (P < .001; 27.6% net relative reduction). Pre-assay, 96% of physicians agreed/strongly agreed that they were confident in their treatment recommendation; post-assay, 90% of physicians agreed/strongly agreed with the same statement. Thirty percent of physicians agreed/strongly agreed that the test had influenced their recommendation, similar to the proportion of changed recommendations. Conclusions The Oncotype DX Assay appears to influence physician ESBC adjuvant treatment recommendations in Hong Kong.published_or_final_versio

Metastasis-suppressing <i>NID2</i>, an epigenetically-silenced gene, in the pathogenesis of nasopharyngeal carcinoma and esophageal squamous cell carcinoma

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Clinical characteristics, laboratory identification, and in vitro antifungal susceptibility of Trichomonascus (Candida) ciferrii isolates associated with granular myringitis

Paper Poster Session - Fungal diagnosis: from culture to molecular techniques: no. P1649BACKGROUND: Trichomonascus (Candida) ciferrii is an emerging opportunistic yeast pathogen that has been increasingly recognised in human infections. T. ciferrii has previously been implicated as the cause of tinea pedis, tinea cruris, onchychomycosis, and less commonly, fungaemia. Recently, we diagnosed four unusual cases of T. ciferrii-associated granular myringitis in Chinese patients in Hong Kong and Shenzhen, China. In this study, we report the clinical characteristics, laboratory identification, and in vitro antifungal susceptibility of T. ciferrii isolates associated with granular myringitis …postprin

Adjuvant and neoadjuvant therapy for gastric cancer using epirubicin/cisplatin/5-fluorouracil (ECF) and alternative regimens before and after chemoradiation

Chemoradiation is now used more commonly for gastric cancer following publication of the US Intergroup trial results that demonstrate an advantage to adjuvant postoperative chemoradiotherapy. However, there remain concerns regarding the toxicity of this treatment, the optimal chemotherapy regimen and the optimal method of radiotherapy delivery. In this prospective study, we evaluated the toxicity and feasibility of an alternative chemoradiation regimen to that used in the Intergroup trial. A total of 26 patients with adenocarcinoma of the stomach were treated with 3D-conformal radiation therapy to a dose of 45 Gy in 25 fractions with concurrent continuous infusional 5-fluorouracil (5-FU). The majority of patients received epirubicin, cisplatin and 5-FU (ECF) as the systemic component given before and after concurrent chemoradiation. The overall rates of observed grade 3 and 4 toxicities were 38 and 15%, respectively. GIT grade 3 toxicity was observed in 19% of patients, while haematologic grade 3 and 4 toxicities were observed in 23%. Our results suggest that this adjuvant regimen can be delivered safely and with acceptable toxicity. This regimen forms the basis of several new studies being developed for postoperative adjuvant therapy of gastric cancer

Test-retest variability of high resolution positron emission tomography (PET) imaging of cortical serotonin (5HT2A) receptors in older, healthy adults

<p>Abstract</p> <p>Background</p> <p>Position emission tomography (PET) imaging using [¹⁸F]-setoperone to quantify cortical 5-HT_2Areceptors has the potential to inform pharmacological treatments for geriatric depression and dementia. Prior reports indicate a significant normal aging effect on serotonin 5HT_2Areceptor (5HT_2AR) binding potential. The purpose of this study was to assess the test-retest variability of [¹⁸F]-setoperone PET with a high resolution scanner (HRRT) for measuring 5HT_2AR availability in subjects greater than 60 years old. Methods: Six healthy subjects (age range = 65–78 years) completed two [¹⁸F]-setoperone PET scans on two separate occasions 5–16 weeks apart.</p> <p>Results</p> <p>The average difference in the binding potential (BP_ND) as measured on the two occasions in the frontal and temporal cortical regions ranged between 2 and 12%, with the lowest intraclass correlation coefficient in anterior cingulate regions.</p> <p>Conclusion</p> <p>We conclude that the test-retest variability of [¹⁸F]-setoperone PET in elderly subjects is comparable to that of [¹⁸F]-setoperone and other 5HT_2AR radiotracers in younger subject samples.</p