A comparative study of protein expression in primary colorectal cancer and synchronous hepatic metastases: the significance of matrix metalloproteinase-1 expression as a predictor of liver metastasis.

Objective: This study was undertaken to determine the ability of protein expression in primary colorectal cancer and metastatic liver tumour tissues to predict hepatic metastasis and intrahepatic recurrence.

Material And Methods: Sixty patients with colorectal cancer were enrolled in this study. The expression of the following five proteins was assessed by immunohistochemical (IHC) staining: carcinoembryonic antigen (CEA); vascular endothelial growth factor (VEGF); matrix metalloproteinase (MMP)-1; MMP-7; and tissue inhibitor of metalloproteinases (TIMP)-1. Protein expression was measured in patients with primary colorectal cancer without liver metastasis (Group A), in patients with primary colorectal cancer with liver metastasis (primary tumour; Group B), and in patients with resected metastatic liver tumour tissues (liver metastasis; Group C).

Results: IHC staining revealed more protease activity (MMP-1 and -7) in Group B than in Group A. Angiogenic activity (positive VEGF expression) was significantly greater in Group C than in Group B. Multivariate analysis showed that positive MMP-1 expression, the presence of lymphovascular invasion, and an elevated pre-operative serum CEA level (> 5 ng/ml) were significantly related to synchronous liver metastasis. However, intrahepatic recurrence was not related to protein expression, the presence of lymphovascular invasion, or the pre-operative CEA level.

Conclusions: Our findings suggest that protease activity is important for metastasis, and that angiogenic activity is essential for metastatic tumour growth. Furthermore, positive MMP-1 expression in primary colorectal tumour tissues was a significant predictor of liver metastasis. However, the prognostic impact of protein marker expression in terms of intrahepatic recurrence appears to be minimal.