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 localisation 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 localisation of Slug in Barrett's metaplasia was largely 
cytoplasmic whilst in 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.