Abstract

The proteolytic processes are thought to be the critical point in tumor invasion and metastasis, mainly by matrix-metalloproteinases (MMPs) and serine proteases. We measured the activities of MMP-9 and MMP-2 in the 120 normal and cancer tissue samples from the same patients using gelatin zymography. Inactive MMP-9(92 kD) was expressed in 73.3% of the normal and 87.5% of the cancer tissues, respectively (p=0.009), while active MMP-9(82 kD) was expressed in 24.2% and 53.3%, respectively (p=0.0001). Inactive MMP-2 (72kD) was expressed in 33.3% of the normal and 55.0% of the cancer tissues, respectively (p=0.001), while active MMP-2(62kD) was expressed in 4.2% and 31.7%, respectively (p=0.0001). In Tl state, only frequency of expression and enzymatic activity of the active MMP-2(62kD) were increased, while from T2 stage, the expression and the activation of the both MMP-9 and MMP-2 were increased as the cancer progressed. The expression frequency of the MMP-9 was more common than of the MMP-2. The co-expression rate of the active forms (82 kD, 62 kD), activites of 82 kD and 62 kD, and the activation rates of the both MMPs were increased as the cancer invades and metastasizes to distant lymph node areas. In conclusion, MMP-2 activation was the main causes of the increased MMPs activity during the Tl phase of the gastric cancer, while production and activation of the both MMP-9 and MMP-2 were increased as the cancer progressed. Therefore, we suggest that the different expression and activation of the MMPs in the gastric cancer progression can be a potential therapeutic target in gastric cancer biotherapy.

• Keywords: MMP-9, MMP-2, Gastric cancer, Invasion, Metastasis