Significance of HER2 protein expression and HER2 gene amplification in colorectal adenocarcinomas

Figure 1 Immunohistochemical staining of human epidermal growth factor receptor 2. A,B: Immunohistochemical staining of human epidermal growth factor receptor 2 in most colorectal adenocarcinomas (CRCs) was scored as either 0 (A) or 1+ (B); C: Approximately 9% of CRCs exhibited 2+ staining; D: Only 2.6% of CRCs exhibited 3+ staining.

Figure 2 Fluorescence in situ hybridization results. By fluorescence in situ hybridization, all tested tumors with 1+ human epidermal growth factor receptor 2 (HER2) staining and 80% of tumors with 2+ staining showed no evidence of HER2 gene amplification (A) whereas 83% of tumors with 3+ HER2 staining harbored HER2 gene amplifications (B).

Figure 3 Kaplan-Meier overall survival analysis. A: Kaplan-Meier overall survival (OS) analysis of colorectal adenocarcinoma patients based on human epidermal growth factor receptor 2 (HER2) expression status (as determined by fluorescence in situ hybridization); B: Kaplan-Meier OS analysis of tubular adenocarcinoma patients age ≤ 65 based on HER2 expression status; C: Kaplan-Meier OS analysis of tubular adenocarcinoma patients with moderate-poor differentiation and age ≤ 65 based on HER2 expression status; D: Kaplan-Meier overall survival analysis of tubular adenocarcinoma patients with stage T2-4 tumors and age ≤ 65 based on HER2 expression status. HER2: Human epidermal growth factor receptor 2; FISH: Fluorescence in situ hybridization.