Published online Apr 21, 2014. doi: 10.3748/wjg.v20.i15.4440
Revised: December 6, 2013
Accepted: January 8, 2014
Published online: April 21, 2014
AIM: To evaluate human epidermal growth factor receptor 2 (HER2) and death decoy receptor (DcR3) as colorectal cancer prognostic indicators.
METHODS: Colorectal carcinoma specimens from 300 patients were analyzed by immunohistochemistry to detect the staining patterns of HER2 and DcR3. Classification of HER2 staining was carried out using the United States Food and Drug Administration semi-quantitative scoring system, with scores of 0 or 1+ indicating a tumor-negative (normal expression) status and scores of 2+ and 3+ indicating a tumor-positive (overexpression) status. Classification of DcR3 was carried out by quantitating the percentage of positive cells within the stained section, with < 10% indicating a tumor-negative status and ≥ 10% indicating a tumor-positive status. Correlation of the HER2 and DcR3 staining status with clinicopathological parameters [age, sex, tumor size, differentiation, and the tumor, node, metastasis (pTNM) classification] and survival was statistically assessed.
RESULTS: Tumor-positive status for HER2 and DcR3 was found in 18.33% and 58.33% of the 300 colorectal carcinoma specimens, respectively. HER2 tumor-positive status showed a significant correlation with tumor size (P = 0.003) but not with other clinicopathological parameters. DcR3 tumor-positive status showed a significant correlation with tumor differentiation (P < 0.001), pTNM stage (P < 0.001), and lymph node metastasis (P < 0.001). However, correlation coefficient analysis did not indicate that a statistically significant correlation exists between tumor-positive status for the HER2 and DcR3 overexpression (P = 0.236). Patients with specimens classified as DcR3-overexpressing had a significantly worse overall survival (OS) rate than those without DcR3 overexpression (median OS: 42.11 vs 61.21 mo; HR = 50.27, 95%CI: 44.90-55.64, P < 0.001). HER2 overexpression had no significant impact on median OS (35.10 mo vs 45.25 mo; HR = 44.40, 95%CI: 39.32-49.48, P = 0.344). However, patients with specimens classified as both HER2- and DcR3-overexpressing had a significantly poorer median OS than those with only HER2 overexpression (31.80 mo vs 52.20 mo; HR = 35.10, 95%CI: 22.04-48.16, P = 0.006).
CONCLUSION: HER2 overexpression is not an independent prognostic marker of colorectal cancer, but DcR3 overexpression is highly correlated with lymph node metastasis and poor OS.
Core tip: Overexpression of the human epidermal growth factor receptor 2 (HER2) and death decoy receptor (DcR3) has been observed in clinical specimens of colorectal cancer, but their roles in prognosis remain unknown. In this systematic investigation of the immunohistochemistry staining patterns of HER2 and DcR3 in 300 clinical specimens, only DcR3 overexpression was identified as a potential prognostic marker of colorectal cancer. Specifically, DcR3 tumor-positive staining showed a strong statistical correlation with lymph node metastasis and poor overall survival. Moreover, HER2-positive patients with DcR3 overexpression had poorer overall survival than their DcR3-negative counterparts.