Wang, Kenneth K.

Background Probe‐based confocal laser endomicroscopy (pCLE) provides microscopic imaging during an endoscopic procedure. Its introduction as a standard modality in gastroenterology has brought significant progress in management strategies, affecting many aspects of clinical care and requiring standardisation of practice and training. Objective This study aimed to provide guidance on the standardisation of its practice and training in Barrett's oesophagus, biliary strictures, colorectal lesions and inflammatory bowel diseases. Methods Initial statements were developed by five group leaders, based on the available clinical evidence. These statements were then voted and edited by the 26 participants, using a modified Delphi approach. After two rounds of votes, statements were validated if the threshold of agreement was higher than 75%. Results Twenty‐six experts participated and, among a total of 77 statements, 61 were adopted (79%) and 16 were rejected (21%). The adoption of each statement was justified by the grade of evidence. Conclusion pCLE should be used to enhance the diagnostic arsenal in the evaluation of these indications, by providing microscopic information which improves the diagnostic performance of the physician. In order actually to implement this technology in the clinical routine, and to ensure good practice, standardised initial and continuing institutional training programmes should be established.

Dysplastic Barrett's esophagus is a condition that offers multiple diagnostic and therapeutic challenges. The diagnosis of dysplasia within Barrett's esophagus currently relies on periodic endoscopic surveillance with multiple biopsies, a methodology limited by random sampling error, inconsistent histopathologic interpretation and delay in diagnosis. Optical spectroscopic and imaging techniques have the potential to identify dysplastic or early neoplastic lesions in real-time. These diagnostic modalities are needed to enhance the endoscopic surveillance of Barrett's esophagus in the future as well as help to define lesions for endoscopic therapy. Esophagectomy has been the standard of care for Barrett's esophagus with high-grade dysplasia although it is a procedure associated with significant morbidity and mortality. Minimally invasive endoscopic ablative therapies are attractive and less morbid alternatives to esophagectomy, with promising results obtained from the use of light-activated drugs (i.e., photodynamic therapy). The combination of novel optical diagnostic techniques and therapies will provide the endoscopist with much needed tools that can considerably enhance the management of patients with Barrett's esophagus. This article reviews the current status and future prospects of optical-based modalities for diagnosis and therapy of dysplastic Barrett's esophagus.

Objective. Guidelines on antiplatelet medication use during endoscopy are based on limited evidence. We investigate the risk of bleeding and ischemic events in patients undergoing endoscopic mucosal resection (EMR) of esophageal lesions in the setting of scheduled cessation and prompt resumption of clopidogrel. Design. Single centre retrospective review. Patients. Patients undergoing EMR of esophageal lesions. Interventions. Use of clopidogrel before EMR and resumption after EMR. Patients cease antiplatelets and anticoagulants 7 days before EMR and resume clopidogrel 2 days after EMR in average risk patients. Main Outcomes. Gastrointestinal bleeding (GIB) and ischemic events (IE) within 30 days of EMR. Results. 798 patients underwent 1716 EMR. 776 EMR were performed on patients on at least 1 antiplatelet/anticoagulant (APAC). 17 EMR were performed following clopidogrel cessation. There were 14 GIB and 2 IE. GIB risk in the setting of recent clopidogrel alone (0%) was comparable to those not on APAC (1.1%) (P=1.0). IE risk on clopidogrel (6.3%) was higher than those not on APAC (0.1%) (P=0.03). Limitations. Retrospective study. Conclusions. Temporary cessation of clopidogrel before EMR and prompt resumption is not associated with an increased risk of gastrointestinal bleeding but may be associated with increased ischemic events.

Abstract Barrett's esophagus is the precursor lesion of esophageal adenocarcinoma, whose progression follows sequential stages. However, the low progression rate and the inadequacy and subjective interpretation of histologic grading in predicting Barrett's esophagus progression call for more objective biomarkers that can improve risk prediction. We conducted a genome-wide profiling of 754 human microRNAs (miRNA) in 35 normal epithelium, 34 Barrett's esophagus, and 36 esophageal adenocarcinoma tissues using TaqMan real-time PCR-based profiling. Unsupervised hierarchical clustering using 294 modestly to highly expressed miRNAs showed clear clustering of two groups: normal epithelium versus Barrett's esophagus/esophageal adenocarcinoma tissues. Moreover, there was an excellent clustering of Barrett's metaplasia (without dysplasia) tissues from normal epithelium tissues. However, Barrett's esophagus tissues of different stages and esophageal adenocarcinoma tissues were interspersed. There were differentially expressed miRNAs at different stages. The majority of miRNA aberrations involved upregulation of expression in Barrett's esophagus and esophageal adenocarcinoma tissues, with the most dramatic alterations occurring at the Barrett's metaplasia stage. Known oncomiRs, such as miR-21, miR-25, and miR-223, and tumor suppressor miRNAs, including miR-205, miR-203, let-7c, and miR-133a, showed progressively altered expression from Barrett's esophagus to esophageal adenocarcinoma. We also identified a number of novel miRNAs that showed progressively altered expression, including miR-301b, miR-618, and miR-23b. The significant miRNA alterations that were exclusive to esophageal adenocarcinoma but not Barrett's esophagus included miR-375 downregulation and upregulation of five members of the miR-17-92 and its homologue clusters, which may become promising biomarkers for esophageal adenocarcinoma development. Cancer Prev Res; 6(3); 196–205. ©2013 AACR.

Pelvic lymph node dissection is the gold standard for assessing nodal disease in prostate or bladder cancer and is superior to CT, MRI and PET staging. Endoscopic ultrasound (EUS) provides an alternative, less invasive method of cytohistologic material acquisition, but its performance in pelvic urologic malignancy is unknown. Therefore, our aim was to evaluate the diagnostic accuracy of EUS guided tissue sampling for these malignancies when compared to a composite cytohistologic and surgical gold standard. A median of 3 FNA passes were performed (n=19 patients) revealing a sensitivity, specificity, PPV and NPV of 94.4% (72–99), 100% (2–100), 100% (80–100) and 50% (1–98) respectively. The perirectal space was the most frequently sampled location irrespective of the primary urological cancer origin. Final diagnosis established by EUS tissue sampling included bladder cancer (n=1), bladder cancer local recurrence (n=8), bladder cancer extra pelvic metastases (n=1), prostate cancer (n=2), prostate cancer local recurrence (n=4), prostate cancer extra pelvic metastases (n=1), testicular cancer extra pelvic metastases (n=1) and a benign seminal vesicle (n=1). EUS guided sampling of the gut wall, lymph nodes, or perirectal space yields suitable diagnostic material to establish the presence of primary, local recurrence or extra pelvic metastases of pelvic urologic malignancy.

Abstract Chromosomal aberrations occur frequently during malignant progression from Barrett's esophagus (BE) to esophageal adenocarcinoma (EAC). In this study, we applied Illumina's 317K high-density SNP arrays to profile chromosomal aberrations at each of the four sequential stages of progression - Barrett's metaplasia (BM), low-grade dysplasia (LGD), high-grade dysplasia (HGD), and EAC. We observed significant trends of increasing LOH/deletion associated with the degree of progression. The average numbers of chromosome arms with LOH/deletion per sample were 0.30, 3.21, 7.70, and 11.90 for BM, LGD, HGD, and EAC, respectively (p-for trend=4.82×10−7). The mean percentages of SNPs with LOH/deletion events were 0.1%, 1.8%, 6.6%, and 17.2% for BM, LGD, HGD, and EAC, respectively (p-for trend=2.64×10−6). In BM, there were scattered chromosome deletions at 3p14.2 (10%), 16q23.1 (5%), and 9p21 (5%), which became predominant aberrations in LGD. More importantly, the 3p14.2 (68.4%) and 16q23.1 (50%) LOH/deletion in LGD was exclusively limited to narrow regions within the FHIT (3p14.2) and WWOX (16q23.1) genes, the two most frequent common fragile sites in the human genome. In contrast, the 9p21 deletion (68.4%) occurred in larger regions (encompassing p16 gene), often involving the whole 9p arm. A significant increase in LOH/deletion of other chromosomes was seen in HGD and there was widespread LOH/deletion across the whole genome in EAC. 17p (47.6%) LOH was the most frequent event in EAC, which mostly spanned the entire 17p arm with only one focal site of LOH at 17p13.1. There were many recurrent small regions of LOH/deletion that disrupted a single gene, most of which are common fragile sites in the human genome. RUNX1 is a potential tumor suppressor gene in EAC. Amplifications were rarer than LOH/deletions. The average numbers of chromosome arms with amplification per sample were 0.30, 0.42, 1.90, and 8.50 for BM, LGD, HGD, and EAC, respectively (p-for trend=1.35×10−9). The mean percentages of SNPs with amplification were 0.5%, 0.4%, 1.5%, and 8.0% for BM, LGD, HGD, and EAC, respectively (p-for trend=1.26×10−8). The most frequent chromosome amplifications in EAC were 8q24.21 (36.6%, MYC), 8p23.1 (31.7%, CTSB), 7q21 (30.8%, CDK6), 20q13.2 (28.6%, ZNF217), and 7p11.2 (25.6%, EGFR). We then analyzed the associations of chromosomal aberrations with clinical features and pathological response in EAC patients treated with neoadjuvant chemoradiation. The number and size of LOH/deletion were significantly associated with pathological response. Non-responders had a greater number (16.4 vs. 8.5, p=0.060) and larger size (662.2 Mb vs. 290.7 Mb, p=0.034) of LOH/deletions, and higher percentage of aberrant SNPs (25.2% vs. 11.2%, p=0.030) than responders. This study provides a genome-wide catalogue of chromosome aberrations occurring during the malignant progression from BE to EAC with the highest resolution to date. Our data support genetic instability and p16 loss as drivers of early neoplastic progression from metaplasia to dysplasia, and p53 aberrations as late events critical for progression to adenocarcinoma. Chromosomal aberrations can predict malignant progression and treatment response in EAC, which may have important clinical implications for cancer prevention and personalized treatment of EAC. Citation Information: Cancer Prev Res 2010;3(1 Suppl):A14.

Abstract Esophageal adenocarcinoma (EAC) is thought to arise from the metaplastic condition known as Barrett's esophagus (BE), which is caused by chronic inflammation due to gastroesophageal reflux disease. Since the molecular mechanisms underlying the pathogenesis of EAC are unknown, understanding EAC development mechanisms and their regulation is crucial for the treatment of EAC. Comparative genomic studies of evolutionarily similar and dissimilar species have been suggested as a means of studying the evolutionary biology in the species. Thus, we performed a cross-species comparison of gene expression patterns in human and rat tissues, uncovering the evolutionarily conserved gene expression patterns during EAC progression across both species. Using a non-carcinogenic rat model that progresses from normal esophagus to BE to EAC, we were able to identify the biological mechanisms of EAC development. We analyzed gene expression data from rat specimens (15 NE, 18 BE, and 30 EAC) as well as from human tissues (28NE, 72BE, and 75EAC). Using the presence of orthologous genes in both microarray platforms and various statistical tests, we uncovered a number of genes whose expression patterns were well conserved during progression from NE to BE in humans and rats. The expression of 869 genes was commonly altered when NE progressed to BE in both humans and rats (P<0.005). One of the most significantly conserved signaling pathways during the progression from NE to BE was IL-6-mediated E2F transcription factor1 (E2F1). The increased E2F1 induced activation of CCNA2, CCNB2, CCND1, CCNE 1 and 2, CDC 2 and 6, CASP3, CASP6, CASP8, CASP9, and Rad 51, which are important genes for the regulation of cell cycle, apoptosis, and DNA repair. These up-regulated genes may consequently cause abnormal cell cycle regulation and induce dysplasia and metaplasia of normal esophagus tissue during NE to BE progression. During BE to EAC progression in both species, 541 gene expressions were altered (P<0.005). An increased TGF-β/RAS/SPI1 signaling pathway significantly increased the expression of SPARC and SPP1 during progression from BE to EAC. Increased SPP1 and SPARC activated MMP9, CCL2, CCL4, COL1A1, COL3A1, and SNAL1, which mostly function in invasion, cell adhesion, and migration. Intriguingly, SPP1 and SPARC already had been discovered in our previous study (Kim et al.,) as markers of poor prognosis for EAC patients, strongly indicating that SPP1 and SPARC are also genetic determinants for progression to EAC. In conclusion, systems-level characterization of gene expression data from humans and a rodent model shows evolutionarily conserved genes and pathways during EAC progression, and these genes and pathways could become reliable biomarkers for early detection, or therapeutic targets for the treatment of EAC patients. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2005.