Expression and clinical significance of C-terminal tensin-like protein in colorectal cancer

Objective To investigate the expression of C-terminal tensin-like (CTEN) protein and its correlations with clinicopathological characteristics and prognosis in patients with colorectal cancer. Methods The retrospective case-control study was adopted. The clinical data of 153 patients with colorectal cancer who were admitted to the Affiliated Hospital of Jiangsu University between January 2010 and December 2012 were collected. The expression of CTEN protein were detected by immunohistochemistry. Observed indices included: (1) expression of CTEN protein was detected by immunohistochemistry. (2) Relationships between the expressions of CTEN protein and clinicopathological characteristics of patients. (3) Relationships between the expressions of CTEN protein and prognosis of patients. The follow-up of telephone interview was performed to detect survival of patients untill May 2015. Count data were analyzed using two-sided chi-square test. Survival curve was drawn using the Kaplan-Meier method, and survival analyses was done using the Log-rank test. Univariate and multivariate analyses of prognosis were done using COX regression model. Results (1) Expressions of CTEN protein in cancer tissues and adjacent tissues were located at the cytoplasms. The positive expression rate of CTEN protein was 92.16%(141/153) and 20.26%(31/153) in cancer tissues and adjacent tissues, respectively, with a statistically significant difference (χ2=160.647, P 0.05). All the 153 patients were followed up for 4.8-62.3 months with a median time of 27.5 months. The 3-year tumor-free survival (Ⅰ-Ⅲ stages) and overall survival (Ⅰ-Ⅳ stages) rates were 52.23% and 39.71% of patients with high expression of CTEN protein, 76.89% and 74.12% in patients with low expression of CTEN protein, respectively, showing significant differences (χ2=15.727, 15.131, P<0.05). Patients with colorectal cancer of Ⅳ stages didn′t achieve R0 resection and were not involved in tumor-free survival. Results of univariate analysis showed that tumor maximum diameter, histologic grade, TNM stage, tumor with perineural and/or vascular invasion and expression of CTEN protein were associated with the prognosis of patients [HR=4.39, 2.08, 5.73, 3.56, 2.03, 95% confidence interval (CI): 2.49-7.74, 2.21-3.55, 3.29-9.98, 1.82-6.95, 1.18-3.48, P<0.05]. Results of multivariate analysis showed that maximum diameter≥5 cm, Ⅳ stage of TNM stage and high expression CTEN protein were independent risk factors affecting the poor prognosis of patients with colorectal cancer (HR=2.24, 3.57, 2.03, 95 %CI: 1.13-4.20, 1.94-6.59, 1.03-3.98, P<0.05). Conclusions The expression of CTEN protein is up-regelated in colorectal cancer compared with adjacent normal tissues. There is increased expression of CTEN protein in colorectal cancer tissues with maximum diameter of tumor ≥5 cm, high TNM stage and perineural and/or vascular invasion. High expression of CTEN protein is also an independent predicting factor of prognosis. Key words: Colorectal neoplasms; C-terminal tensin-like protein; Prognosis; Immunohistochemical staining