Expression of HGF and Met in Human Tissues of Colorectal Cancers: Biological and Clinical Implications for Synchronous Liver Metastasis

Background and aims: Synchronous liver metastasis (SLM) remains a significant problem in newly diagnosed colorectal cancer (CRC). The system of hepatocyte growth factor (HGF) and Met plays an important role in cancer invasion and metastasis and is being developed to be targeted drugs. We aimed to investigate the role of HGF/Met in SLM based on a case-matched study and comparison between primary tumors and matched metastases. Methods: A group of 30 patients with SLM and other two groups of patients without SLM in a hospital database were collected. They were matched into according to clinicopathological factors. 81 patients were included in the study. Their tissues of primary colorectal cancers, lymph nodes and liver metastases were collected to detect HGF and Met expression by immunohistochemistry and RT-PCR. Results: Expression of HGF and Met at the protein level and the RNA level in primary CRCs with SLM were significantly higher than that in primary colorectal carcinomas without liver metastases (all P value<0.05). Their expression was only related to SLM when concurrent with regional lymph node metastasis (all P value<0.05) but had little influence on SLM without involvement of lymph node metastasis (all P value>0.05). Comparison their expression between primary tumors and matched metastases, major concordance and minor difference existed. Conclusions: HGF and Met may exert functions in the development of SLM when concurrent with lymph node metastases but had little influence on SLM without lymph node metastasis, further indicating their roles and potential values for a subtype of colorectal cancer metastasis. Major concordance and minor difference exist between primary tumors and matched metastases, which further provides evidence for evaluating the response to their inhibitors based on primary tumors or metastases.