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AIM:To characterise expression of known E-cadherin repressors; Snail , Slug and Twist in the development of esophageal adenocarcinoma.METHODS: E-cadherin , Slug , Snail and Twist mRNA expression in Barrett's metaplasia and esophageal adenocarcinoma specimens was examined by real-time reverse transcription-polymerase chain reaction (RT-PCR). Semi-quantitative immunohistochemistry was used to examine cellular localization and protein levels. The effect of Slug on epithelial mesenchymal transition (EMT) markers was examined by transfection of Slug into an adenocarcinoma line OE33.RESULTS: Cellular localization of Slug in Barrett's m e t a p l a s i a w a s l a r g e l y c y t o p l a s m i c w h i l s t i n adenocarcinoma it was nuclear. Semi-quantitative analysis indicated that Slug was more abundant in adenocarcinoma compared to matched Barrett's metaplastic specimens. Snail and Twist were expressed in adenocarcinoma but were cytoplasmic in location and not induced compared to Barrett's mucosa. These observations were supported by mRNA studies where only Slug mRNA was shown to be over-expressed in adenocarcinoma and inversely correlated to E-cadherin expression. Overexpression of Slug in OE33 mediated E-cadherin repression and induced the mesenchymal markers vimentin and fibronectin.CONCLUSION: Progression to adenocarcinoma is associated with increased Slug expression and this may represent a mechanism of E-cadherin silencing.

Peroral endoscopic myotomy (POEM) is a novel approach to performing esophageal myotomy for the treatment of achalasia. This review aims to assess subjective and objective metrics of achalasia treatment efficacy, perioperative adverse events and the incidence of postoperative gastroesophageal reflux disease in patients treated with POEM. Secondary aims include a pooled analysis comparison of the clinical outcomes and procedural safety of POEM versus laparoscopic Heller's myotomy (LHM). A systematic review of the literature, up to and including January 15, 2015, was conducted for studies reporting POEM outcomes. Studies comparing POEM to LHM were also included for the purpose of pooled analysis. Outcomes from 1122 POEM patients, from 22 studies, are reported in this systematic review. Minor operative adverse events included capno/pneumo-peritoneum (30.6%), capno/pneumo-thorax (11.0%) and subcutaneous emphysema (31.6%). Major operative adverse events included mediastinal leak (0.3%), postoperative bleeding (1.1%) and a single mortality (0.09%). There was an improvement in lower esophageal sphincter pressure and timed barium esophagram column height of 66% and 80% post-POEM, respectively. Symptom improvement was demonstrated with a pre- and post-POEM Eckardt score ± standard deviation of 6.8 ± 1.0 and 1.2 ± 0.6, respectively. Pre- and post-POEM endoscopy showed esophagitis in 0% and 19% of patients, respectively. The median (interquartile range) points scored for study quality was 15 (14-16) out of total of 32. Pooled analysis of three comparative studies between LHM and POEM showed similar results for adverse events, perforation rate, operative time and a nonsignificant trend toward a reduced length of hospital stay in the POEM group. In conclusion, POEM is a safe and effective treatment for achalasia, showing significant improvements in objective metrics and achalasia-related symptoms. Randomized comparative studies of LHM and POEM are required to determine the most effective treatment modality for achalasia.

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