Plasma matrix metalloproteinase-9 level is better than serum matrix metalloproteinase-9 level to predict gastric cancer evolution

PURPOSE

Matrix metalloproteinase-9 (MMP-9) in blood is a promising new tumor marker. The aims of the present study are to compare the usefulness of plasma and serum MMP-9 levels for predicting gastric cancer development, invasion, and survival.

EXPERIMENTAL DESIGN

In this nested case-control study, 114 gastric cancer patients and 87 healthy controls were enrolled. MMP-9 levels and activities were quantitatively measured by ELISA assay and zymography. The results were compared with the occurrence, clinicopathologic features, and outcomes of gastric cancer patients. The follow-up time for all patients was at least 5 years.

RESULTS

Serum MMP-9 levels were significantly higher than plasma MMP-9 levels. Both plasma and serum MMP-9 levels correlated significantly with active MMP-9 identified by zymography (P = 0.002 and P = 0.048, respectively). Plasma MMP-9 level was significantly elevated in gastric cancer patients when compared with control subjects (P < 0.001). Serum MMP-9 levels did not differ between the groups. Receiver-operator characteristics analysis showed the values of sensitivity (82.5%) and specificity (65.5%) at the maximum accuracy for plasma MMP-9 at >or=60 ng/mL (P < 0.001). Elevated plasma MMP-9 correlated significantly with lymph node metastasis [odds ratio (OR), 3.43; P = 0.019], lymphatic invasion (OR, 7.58; P = 0.009), and venous invasion (OR, 4.14; P = 0.033). Patients with elevated plasma MMP-9 levels had poorer survival rates than those with normal plasma MMP-9 levels (P = 0.038). Serum MMP-9 level did not correlate well with gastric cancer-invasive phenotypes or survival.

CONCLUSION

Our results suggest plasma MMP-9 level is a better marker than serum MMP-9 level for predicting gastric cancer development and progression.

The prognostic value of p53, Ki-67 and matrix metalloproteinases MMP-2 and MMP-9 in transitional cell carcinoma of the renal pelvis and ureter

AIM

To investigate the prognostic and predictive relevance of p53 protein, Ki-67 antigen, MMP-2 and MMP-9 in patients with transitional cell carcinoma (TCC) of the upper urinary tract.

METHODS

The expression of p53 protein, Ki-67 antigen, MMP-2 and MMP-9 was examined by immunohistochemistry in 69 patients with TCC of the upper urinary tract. Correlation of p53, Ki-67, MMP-2 and MMP-9 over-expression with conventional pathological parameters and patient survival was examined.

RESULTS

p53 over-expression was significantly correlated with histological grade (P < 0.05), but not with pathological stage, vascular invasion, lymphatic invasion or lymph node metastasis. Ki-67 over-expression was significantly correlated with stage, grade, lymphatic invasion and vascular invasion (P < 0.05). In survival analyses, Ki-67 over-expression was a significant prognostic factor in the univariate analysis (P < 0.05), but it did not have a significant impact on survival in the multivariate analysis. Ki-67 labeling index was a significant prognostic factor in patients with a low p53 labeling index, but not in patients with a high p53 labeling index.

CONCLUSION

Ki-67 over-expression is of prognostic value in TCC of the upper urinary tract, while p53, MMP-2 and MMP-9 are of limited value.

Fluorogenic MMP activity assay for plasma including MMPs complexed to alpha 2-macroglobulin

Elevated MMP activities are implicated in tissue degradation in, e.g., arthritis and cancer. The present study was designed to measure MMP enzyme activity in plasma. Free active MMP is unlikely to be present in plasma: upon entering the circulation, active MMP is expected to be captured by the proteinase inhibitor alpha 2-macroglobulin (alpha 2M). Reconstituted MMP-13/alpha 2M complex was unable to degrade collagen (MW 300,000) in contrast to the low-molecular-weight fluorogenic substrate (MW < 1500). Limited access of high-MW substrates to the active site of MMPs captured by alpha 2M presents the most likely explanation. Consistently, the high-MW inhibitor TIMP (MW approximately 28,000) was unable to inhibit MMP/alpha 2M enzyme activity, whereas the low-MW inhibitor BB94 (MW approximately 500) effectively suppressed enzyme activity. By using fluorogenic substrates with Dabcyl/Fluorescein as quencher/fluorophore combin-ation, sensitive MMP-activity assays in plasma were achieved. Spiking of active MMP-13 and MMP-13/alpha 2M complex, and inhibitor studies with TIMP-1 and BB94, indicated that active MMPs are efficiently captured by alpha 2M in plasma. MMP activity was even detected in control plasma, and was significantly increased in plasma from rheumatoid arthritis patients.

MMP-9 activity in urine from patients with various tumors, as measured by a novel MMP activity assay using modified urokinase as a substrate

Matrix metalloproteinases (MMPs) play an important role in many pathologic processes, but their activities are difficult to determine since no simple specific and/or chromogenic substrate exists. We have developed a novel MMP activity assay using a modified urokinase as a substrate. Protein engineering enabled the plasmin activation site in this urokinase to be substituted by a specific activation site recognized by MMPs. In this way the MMP activity can be monitored via urokinase activity as measured by a simple chromogenic assay. The assay was made specific for MMP-9 by a capture step using MMP-9-specific antibodies that do not interfere with MMP-activity. This assay monitors the amount of active enzyme as well as the latent, but potentially active proform. Using this assay the levels of MMP-9 were investigated in urine from patients with various kinds of carcinoma. High levels of both active and latent MMP-9 were detected in urine from patients with carcinoma of the bladder, whereas hardly any activity was observed in urine from healthy controls. MMP-9 in urine was present in its intact form. Surprisingly, MMP-9 was also increased in the urine of patients with nonurogenital carcinoma. Therefore, measurement of urinary MMP-9 activity levels may be a convenient diagnostic tool for various types of carcinoma.