ILEI: a novel marker for epithelial-mesenchymal transition and poor prognosis in colorectal cancer

Accumulating evidence over the past decade has shown that abnormal activation of epithelial to mesenchymal transition (EMT) contributes to tumour progression and metastasis in colorectal cancer (CRC). In this study, we investigated the expression of interleukin-like EMT inducer (ILEI) and EMT-associated markers (E-cadherin, vimentin) in CRC tissues and determined the correlations between ILEI expression and clinicopathological characteristics, prognosis and EMT in CRC.

In total, 194 patients diagnosed with CRC based on histopathological evaluation and those subjected to surgical resection at the First Hospital of China Medical University between 2003 and 2005 were examined. Immunohistochemical staining for ILEI, vimentin and E-cadherin was performed for each specimen. Cytoplasmic overexpression of ILEI usually accompanied down-regulation of E-cadherin and positive expression of vimentin. Conversely, ILEI was simultaneously down-regulated with overexpression of E-cadherin and negative expression of vimentin. ILEI overexpression was associated significantly with T-stage, N-stage, TNM stage and EMT phenotype (P = 0.024, <0.001, <0.001 and <0.001, respectively). Multivariate analysis revealed that ILEI expression was an independent prognostic factor for patient survival.

Our findings indicate that cytoplasmic ILEI expression is a potential marker of EMT and tumour progression in CRC. ILEI is an independent predictive factor associated with poor prognosis in CRC.