Precise measurement of the E-cadherin repressor Snail in formalin-fixed endometrial carcinoma using protein lysate microarrays

Over-expression of the zinc finger transcription factor Snail leads to down-regulation of the epithelial proteins E-cadherin and Cytokeratin 18 and to upregulation of the mesenchymal protein Vimentin. The aim of our study was to characterize for the first time Snail protein expression in formalin-fixed primary tumour tissues using protein lysate microarrays and correlate Snail with E-cadherin, Cytokeratin 18, and Vimentin protein abundances. In a first feasibility study, we examined 17 formalin-fixed endometrioid adenocarcinomas by protein lysate microarrays. Snail expression showed a statistical significant inverse correlation with the expression of E-cadherin (P < 0.001). A trend for correlation between Snail and Cytokeratin 18 (P = 0.043) and the tumour grade (P = 0.074) was seen. For Snail and Vimentin no correlation was found (P = 0.384). In conclusion, our results fit to the proposed function of Snail as a transcriptional repressor of E-cadherin and Cytokeratin 18 in primary human carcinomas and demonstrate the usefulness of protein lysate microarrays for the precise determination of proteins involved in epithelial-mesenchymal-transition.