HER3 expression in primary colorectal cancer including corresponding metastases in lymph node and liver.

BACKGROUND: The human epidermal growth factor receptor complex (EGFR-1, HER2, HER3 and HER4) plays an important role in pathogenesis of solid tumours. We have previously reported high expression of HER3 in 70% of primary colorectal cancer (CRC) and that high expression were linked to a worse clinical outcome. The purpose of this study is to evaluate the HER3 expression in primary CRC and metastases. MATERIAL AND METHODS: Tissue samples from primary CRC, corresponding lymph node metastases and liver metastases from 107 patients were analysed by immunohistochemistry. RESULTS: Of 107 patients, 80% showed high HER3 expression in primary CRC tumours and 81% of the stage III patients presented high expression in the lymph node metastases. All patients had liver metastases and 82% presented high HER3 expression. HER3 expression in primary tumour correlated with expression in the corresponding lymph node metastases (r = 0.65, p < 0.001) and in the liver metastases (r = 0.45, p < 0.001). A correlation between HER3 expression in corresponding lymph node and liver metastases (r = 0.65, p < 0.001) was seen. CONCLUSION: High HER3 expression is seen in about 80% of primary CRC, corresponding lymph node metastases and liver metastases. There is a correlation between HER3 expression in primary tumour and metastases in CRC.