Reduced expression of EphA5 is associated with lymph node metastasis, advanced TNM stage, and poor prognosis in colorectal carcinoma

Colorectal carcinoma (CRC) is the third most common cancer and a major cause of morbidity and mortality throughout the world. The prognosis of patients has improved markedly over the last 15 years because of the introduction of new therapy including molecular target drugs. To comprehensively understand the molecular process of carcinogenesis of colorectal carcinoma is essential for the diagnosis, prognosis and treatment. EphA5 is a member of the Eph family and plays a critical role in carcinogenesis of lung cancer, prostate cancer, and breast cancer. The expression profile and the role of EphA5 in colorectal carcinoma have not been well investigated till now. In this study, a set of colorectal carcinoma specimens was subjected to immunohistochemical assay using an EphA5 specific antibody. The relationship between the expression of EphA5 and clinicopathological parameters was statistically analyzed. EphA5 was positively expressed in all tested normal mucosa specimens (120/120, 100%) and partly in colorectal carcinoma specimens (70/120, 58.3%). The loss of EphA5 protein was associated with depth of wall invasion (P= 0.002), poor tumor differentiation (P<0.001), lymph node metastasis (P<0.001), and advanced TNM stage (P<0.001). The survival analysis showed that patients with reduced expression of EphA5 had a poor overall survival (P=0.017). Our data indicate that EphA5 receptor may be a tumor suppressor in colorectal carcinoma and it may be a new therapeutic target for colorectal carcinoma.