Abstract: Objective To examine the expression level of interferon-induced transmembrane protein1（IFITM1） and assess its clinical significance in colorectal cancer. Methods Tissue microarrays were constructed from 144 paraffinembedded tissue blocks containing colorectal cancer with corresponding normal epithelium， and the expression of IFITM1 was tested by immunohistochemistry. The correlations between IFITM1 expression， the clinicopathological factors and overall survival rate were evaluated.
Results Immunohistochemistry demonstrated that strong （7.7％）， moderate （36.9％） and weak （55.4％） expression rate of IFITM1 in colonic cancer tissue were higher than those of adjacent noncancerous tissue（7.7％，36.9％ and 55.4％），with significant difference（P=0.044）. The strong （1.3％）， moderate （39.2％） and weak （59.5％） expression rate of IFITM1 in rectal adenocarcinoma showed no statistic significance compared with （5.1％， 36.9％ and 58.2％）， with no difference （P=0.569）.The expression of IFITM1 was significantly correlated with histological differentiation （P=0.031）. However， the gender， age， tumor location， depth of invasion， lymph node metastasis， and TNM stage had no significant correlation with IFITM1 expression. OS of colorectal cancer patients with high, moderate, low expression of IFITM1 were 34.3, 45.7 and 46.7 months（P=0.700）. Moreover， Kaplan-Meier survival analysis demonstrated that patients with higher IFITM1 expression had worse overall survival outcomes than those with lower levels of IFITM1 expression in rectal cancer （P=0.037）. Mean survival of rectal cancer patients with IFITM1 high expression， moderate expression and low expression was 15.0， 42.7 and 50.1 months respectively. IFITM1 expression was not a significant negative prognostic factor for survival by univariate or multivariate analyses. Conclusion The results suggest that the expression of IFITM1 is associated with poor prognosis in rectal adenocarcinoma. IFITM1 may be a biomarker to predict prognosis in patients with rectal adenocarinoma.