OBJECTIVETo explore the expression of NF-E1b in colorectal cancer tissues and its association with various clinicopathological parameters and prognosis of the patients.

METHODSClinicopathological and follow-up data of 168 colorectal cancer patients undergoing radical operation at Department of Gastrointestinal Surgery, Peking University Cancer Hospital and Institute from 2005 to 2012 were retrospectively analyzed, including 96 males and 72 females, with mean age of (57.8±11.2) years. The expression of NF-E1b protein was detected in samples of 168 resected colorectal cancer tissues and 45 adjacent non-cancerous tissues by immunohistochemistry. The expression rates of NF-E1b were compared among different clinicopathological features. Moreover, the association between NF-E1b expression and prognosis was analyzed.

RESULTSThe expression of NF-E1b protein located mainly in cytoplasm. Positive rate of NF-E1b expression in adjacent non-cancerous tissues was 17.8% (8/45), which was obviously lower than 67.9%(114/168) of cancer tissues with significant difference (χ(2)=36.376, P=0.000). Clinicopathological parameters analysis suggested that the expression level of NF-E1b in cancer tissues was associated with age (χ(2)=4.862, P=0.030), TNM staging (χ(2)=10.969, P=0.002), lymph node metastasis (χ(2)=7.390, P=0.008) and distal metastasis (χ(2)=17.887, P=0.000). The median follow-up time was 23(1-77) months. The overall 5-year survival of this cohort was 33.3%. Colorectal cancer patients with high levels of NF-E1b expression showed a worse overall survival compared with those with low levels of NF-E1b expression (18.4% vs. 56.6%, P=0.000). Univariate Cox regression analysis showed that tumor location (P=0.034), tumor size (P=0.003), TNM staging (P=0.000), depth of tumor invasion (P=0.009), lymph node metastasis (P=0.000), distant metastasis (P=0.000) and NF-E1b expression level (P=0.001) were associated with the prognosis of colorectal cancer patients. Multivariate Cox regression analysis revealed that tumor diameter >4 cm (HR=2.193,95% CI:1.334 to 3.603, P=0.002), distant metastasis (HR=2.064, 95% CI:1.160 to 3.672, P=0.014) and high NF-E1b expression (HR=1.994,95% CI:1.068 to 3.724, P=0.030) were independent risk factors of predicting poor prognosis of colorectal cancer patients.

CONCLUSIONSNF-E1b expression up-regulates in colorectal cancer tissues. High expression of NF-E1b is associated with poor prognosis of colorectal cancer patients. NF-E1b may serve as a potential target of the treatment for colorectal cancer.