RESUMEN
INTRODUCTION: Matrix metalloproteinases (MMPs) are overexpressed at different stages of colorectal carcinogenesis and could serve as early surrogate biomarkers of colorectal neoplasia. OBJECTIVE: To assess the utility of plasma MMP2 and MMP9 levels in the detection of advanced colorectal neoplasia and their correlation with tissue levels. METHODS: We analysed blood and tissue samples from patients with non-advanced adenomas (n=25), advanced adenomas (n=25), colorectal cancer (n=25) and healthy controls (n=75). Plasma and tissue gelatinase levels were determined by Luminex XMAP technology and gelatin zymography. Receiver operating characteristic (ROC) curve analysis was used to calculate the optimum cut-off for the detection of advanced colorectal neoplasia. RESULTS: Plasma MMP2 levels were similar between groups whatever the type of lesion. Plasma MMP9 levels were significantly higher in patients with neoplastic lesions than in healthy controls (median 292.3ng/ml vs. 139.08ng/ml, P<0.001). MMP9 levels were also higher in colorectal cancer than in non-advanced adenomas (median 314.6ng/ml vs. 274.3ng/ml, P=0.03). There was a significant correlation between plasma and tissue levels of MMP9 (r=0.5, P<0.001). The plasma MMP9 cut-off range with the highest diagnostic accuracy was between 173ng/ml and 204ng/ml (AUC=0.80 [95% CI: 0.72-0.86], P<0.001; sensitivity, 80-86% and specificity, 57-67%). CONCLUSION: Plasma MMP9 could be a surrogate biomarker for the early detection of advanced colorectal neoplasia, although its diagnostic performance could be increased by combination with other biomarkers.