High Level of Notch1 Protein is Associated with Poor Overall Survival in Colorectal Cancer

Notch1 regulates cell proliferation, development, and apoptosis. Aberrant expression of Notch1 has been discovered in many types of tumors. We examined Notch1 expression in colorectal cancer to assess its role as a prognostic indicator. Notch1 protein expression was examined by immunohistochemistry in 223 surgically resected specimens of colorectal cancer and adjacent tissues. The relationship between various clinicopathological features and overall patient survival rate was analyzed. The association of Notch1 expression with the colorectal cancer survival rate was assessed by Kaplan-Meier and Cox proportional-hazards regression. Significantly high Notch1 expression was found in colorectal cancer cells compared with that of normal colorectal epithelial cells. Notch1 was positively correlated with depth of invasion (P = 0.005), lymph node metastases (P = 0.03), and tumor-node-metastasis (TNM) stage (P < 0.001). Consistently, the overall survival rate was significantly lower for patients with Notch1-positive than those with Notch1-negative tumors. However, no correlation between Notch1 expression and patient age, sex or tumor location was found. Notch1 might serve as a novel prognostic marker that is independent of, and additive to, the TNM staging system.