HER2 and HER3 expression in hepatic metastases of colorectal cancer: New targets for specific treatment approaches?

Abstract

567 Background: Even though treatment options for coloretal cancer liver metastases have improved with the implementation of multimodal strategies and new agents, progression of distant metastases is still limiting the prognosis of affected patients. In this context we investigated the expression of HER2 and HER3 in patients with metastatic colorectal cancer and primary tumors. Methods: In this study 226 consecutive patients with hepatic metastases of colorectal cancer were included. HER2 and HER3 expression were determined in the tissue from resected metastases and—if available—in primary tumors. Immunohistochemical scoring (IHC 0 to IHC 3) and S-ISH-amplification-detection (for HER2) were used to determine the HER2 and HER3 status. Results: A positive HER2 status was found in 8.4% of all hepatic metastases; an overexpression of HER-3 in 74,8% of all cases. There was a high congruence of the expression pattern of HER2 and HER3 between hepatic metastases and available primary tumors (>90%). Conclusions: HER2 amplification and HER3 overexpression is detectable in a significant proportion of hepatic metastases of colorectal cancer. These results suggest that innovative new targeted treatment agents might be possible opportunities for the specific therapy of patients with HER2/HER3 positive metastatic colorectal cancer and should be further assessed within prospective clinical trials.