Prediction of lymph node metastasis and prognosis in colorectal cancer patients using slug and vimentin expression.

e14029 Background: Slug plays a critical role in regulating the epithelial-mesenchymal transition (EMT) by down-regulation of epithelial markers and up-regulation of mesenchymal markers. The purpose of the present study was to evaluate the clinical significance of Slug and Vimentin expression in colorectal cancer (CRC) and to perform in vitro characterization of Slug’s function. Methods: At first, the biological role of Slug in CRC was assessed by RNA interference in CRC cell lines to assess tumor progression, invasion and migration. We next analyzed Slug and Vimentin expression in surgical tissue specimens from 181 CRC patients by quantitative reverse transcriptase polymerase chain reaction and immunohistochemistry. Results: Knockdown of Slug in siRNA knockdown studies resulted in induction of EMT markers, inhibited cancer cell proliferation, invasion and migration abilities. Slug and Vimentin expression in cancer tissues was significantly higher in patients with high T stage, lymph node involvement, liver metastasis and advanced TNM stage. We also observed a significant correlation between Slug and Vimentin expression in CRC (rho = 0.467). Increased Slug and Vimentin expression were significantly associated with poor prognosis in Stage I-IV (p<0.0001, p=0.0005, log-rank test) and Stage II (p= 0.04, p=0.012, log-rank test) Furthermore, increased Slug expression was an independent predictive marker of lymph node metastasis (p=0.012) and prognostic factor (p= 0.025). Conclusions: Our data demonstrate that evaluation of Slug and Vimentin could be valuable in the identification of patients with lymph node metastasis or poor prognosis in CRC.