Shyam Thakkar

MicroRNA signature characterizes primary tumors that metastasize in an esophageal adenocarcinoma rat model.

Objective To establish a miRNA signature for metastasis in an animal model of esophageal adenocarcinoma (EAC). Background The incidence of esophageal adenocarcinoma (EAC) has dramatically increased and esophageal cancer is now the sixth leading cause of cancer deaths worldwide. Mortality rates remain high among patients with advanced stage disease and esophagectomy is associated with high complication rates. Hence, early identification of potentially metastatic disease would better guide treatment strategies. Methods The modified Levrat’s surgery was performed to induce EAC in Sprague-Dawley rats. Primary EAC and distant metastatic sites were confirmed via histology and immunofluorescence. miRNA profiling was performed on primary tumors with or without metastasis. A unique subset of miRNAs expressed in primary tumors and metastases was identified with Ingenuity Pathway Analysis (IPA) along with upstream and downstream targets. miRNA-linked gene expression analysis was performed on a secondary cohort of metastasis positive (n=5) and metastasis negative (n=28) primary tumors. Results The epithelial origin of distant metastasis was established by IF using villin (VIL1) and mucin 5AC (MUC5AC) antibodies. miRNome analysis identified four down-regulated miRNAs in metastasis positive primary tumors compared to metastasis negative tumors: miR-92a-3p (p=0.0001), miR-141-3p (p=0.0022), miR-451-1a (p=0.0181) and miR133a-3p (p=0.0304). Six target genes identified in the top scoring networks by IPA were validated as significantly, differentially expressed in metastasis positive primary tumors: Ago2, Akt1, Kras, Bcl2L11, CDKN1B and Zeb2. Conclusion In vivo metastasis was confirmed in the modified Levrat’s model. Analysis of the primary tumor identified a distinctive miRNA signature for primary tumors that metastasized.

Endoscopic Myotomy of Zenker's Diverticulum Using A Novel Electrosurgical Knife: First Reported Case in the USA

Zenkers diverticulum (ZD) is a relatively uncommon esophageal pathology with significant morbidity typically presenting in the elderly population. Symptoms often include dysphagia, halitosis, regurgitation, and food retention [1]. Current treatment options include open surgical cricopharyngeal myotomy/diverticulectomy and rigid or flexible endoscopic techniques. Previous reports have shown decreased rates of complications, as well as shorter procedure and hospitalization times with flexible endoscopic repair. This article is protected by copyright. All rights reserved.

Retroperitoneal Leiomyosarcoma Presenting as Lower Gastrointestinal Bleeding: A Case Report and Review of the Literature

We report the first known case of a retroperitoneal leiomyosarcoma that presented with an endoscopically defined source of gastrointestinal bleeding in the colon. A 68-year-old male with a history of diverticulosis, hypertension, and hypercholesterolemia who complained of a 3-month history of abdominal pain, nausea, and intermittent hematochezia presented for evaluation of large volume hematochezia and lightheadedness. Colonoscopy revealed left-sided diverticulosis and rectal varices without stigmata of recent bleed. CT scan showed a 26 × 20 × 13 cm heterogeneous retroperitoneal mass and multiple hypodense hepatic lesions. Liver biopsy revealed leiomyosarcoma. In summary, although surgery is the mainstay of treatment, resectability has not improved significantly. Early recognition and aggressive surgery are keys to long-term survival.