Clinical Significance of Matrix Metalloproteinases in Blood Plasma of Patients with Gastric Cancer

Plasma levels of MMP-2, MMP-7, and MMP-9 and their tissue inhibitor TIMP-2 were measured in 89 patients with gastric cancer and the relationship between these parameters and the main clinical morphological characteristics of the disease was analyzed. Plasma levels of the proteins were measured using standard direct ELISA kits. The level of MMP-7 in patients with gastric cancer was significantly higher than in the control group (medians 2.7 and 1.2 ng/ml, respectively; p<0.01), but only in 51% patients this parameter surpassed the upper threshold normal value (2.35 ng/ml; 95% percentile of control). The level of MMP-9 in gastric cancer patients was lower than in control group by 1.6 times (medians 167 and 267 ng/ml, respectively; p<0.01). Plasma levels of MMP-2 and TIMP-2 in patients with gastric cancer and healthy subjects were similar. No appreciable associations of plasma matrixins and TIMP-2 with the main clinical morphological characteristics of the disease were detected. The patients were followed up for 8 to 85 months (median 70.8 months). Low level of MMP-2 and high level of MMP-7 in the plasma proved to be unfavorable prognostic factors for overall survival. At MMP-2<268 ng/ml, the 5-year overall survival was 32% vs. 60% for patients with the marker level higher than this threshold value (p=0.016). The differences in overall survival in relation to their MMP-7 levels for 5-year observation did not surpass 16% (39% at marker level >2.7 ng/ml and 55% at lower level; p=0.048). Plasma levels of MMP-2 and TIMP-2 were not significantly associated with overall survival. Multivariate analysis showed that only T index (p=0.034) and plasma MMP-7 level (p=0.007) were essential for overall survival. The increase in plasma or serum MMP-7 levels is a universal phenomenon in tumors of different histogenesis, which precluded the use of this parameter as a specific diagnostic marker of gastric cancer. At the same time, it could be useful for monitoring the treatment efficiency and detection of relapses. In addition, high plasma level of MMP-7 remained an independent factor of unfavorable prognosis for overall survival of patients with gastric cancer.