Expression and significance of Snail and Claudin-3 in non-small cell lung cancer

Epithelial-mesenchymal transition (EMT) is considered to be one of the major molecular mechanisms inducing tumor invasion and metastasis. The loss of epithelial cell polarity is a hallmark of the EMT process. Epithelial markers such as Claudin are lost in EMT. Snail is a major transcription factor governing EMT. Recent studies about the mechanism of tumor invasion and metastasis has proven that Snail could enhance the ability of many tumors' invasiveness. The aim of this study is to investigate the expression of Snail and Claudin-3 in non-small cell lung cancer (NSCLC) and its metastatic lymph node with tissue microarray technique, and to explore clinical significance of these two molecules expression in NSCLC. Snail and Claudin-3 proteins were detected in cases of 59 adjacent normal lung tissues, 302 cases of primary NSCLC and 57 cases of lymph node metastatic tissues by MaxVision and EnVision method of immunohistochemical staining respectively. The expression of Snail in adjacent normal lung tissues, NSCLC