Prognostic value of epidermal growth factor receptor and nm23 expression in patients with rectal cancer and its guiding significance for treatment

Abstract

Objective To evaluate the predictive value of epidermal growth factor receptor (EGFR) and nm23 expression and its guiding role of choosing chemotherapy regimen in post-operation patients with rectal carcinoma. Methods The expression of EGFR and nm23 in 243 specimens of rectal carcinoma tissues was examined by immunohistochemistry. The clinical and pathological data were recorded, and patients were followed up for more than five years. Kaplan-Meier estimates, Cox proportional hazard regression and hierarchical analyses were employed to assess the correlation between the expression of EGFR and nm23 in rectal carcinoma and the progression free survival (PFS) of patients treated with the different surgical methods and chemotherapy. Results EGFR and nm23 were expressed proportionately in rectal cancer tissues. Kaplan-Meier showed that EGFR expression is negatively related to the PFS of the post-operative patients. The median PFS was 21.0 months in the patients with high expression, and that was 37.8 months in the patients with low expression (χ2=8.687, P=0.003). The nm23 expression was positively associated with the PFS of the post-operative patients. The median PFS was 35.4 months in the patients with high expression, and that was 13.4 months in the patients with low expression (χ2=15.593, P=0.001). The median PFS was longer in the patients with low EGFR expression and high nm23 expression (median PFS=62.9 months, χ2=18.227, P=0.000). The univariate analyses revealed that the patients with low EGFR expression and high nm23 expression had longer PFS than in those with high EGFR expression and low nm23 expression[hazard ratio (HR)=2.290, 95% confidence interval (CI): 1.548-3.387, P=0.000]. Multivariate analysis (Cox) showed that low EGFR expression and high nm23 expression was an independent combined predictor of longer PFS (HR=1.966, 95%CI: 1.319-2.929, P=0.001). In addition, hierarchical analysis also suggested that post-Dixon operation patients with low EGFR expression and high nm23 expression had significantly longer survival time than other patients, and also were more sensitive to chemotherapy with FOLFOX4 regimen than other patients (median PFS=61.1 months, χ2=8.218, P=0.004). Conclusion EGFR and nm23 have predictive value for the prognosis of post-operative patients with rectal carcinoma and are an ideal combination of predictive factors. Key words: Epidermal growth factor receptor; nm23; Rectal carcinoma