Reduced expression of tissue inhibitor of metalloproteinase in nodal metastasis of stomach cancer.

The matrix metalloproteinases (MMPs) have been associated with tumor cell invasion and metastasis of human cancers by mediating the degradation of extracellular matrix components. Therefore, these enzymes and their inhibitor (TIMP-2) constitute promising targets in the development of anticancer therapies. In order to investigate the correlation between expressions of TIMP-2, MMPs and clinical outcome, immunohistochemical staining of MMP-2, MMP-9, and TIMP-2 were performed on paraffin-embedded tissue sections of 15 early gastric cancers (EGC) and 15 advanced gastric carcinomas (AGC) without nodal metastasis and 15 AGC with nodal metastasis (AGCn+). MMP-2 and MMP-9 were expressed in neoplastic cell plasma membrane in 83.3% and 88% of cases of AGC, respectively with inter-tumoral variability of staining intensity. MMP-2 and MMP-9 staining were not correlated with presence of nodal metastasis or degree of invasion depth at the time of diagnosis (p>0.05). The immunoreactivity of TIMP-2 was detected in the peri-tumoral stroma. Residual benign stomach tissue showed no or weak immunoreactivity for TIMP-2 staining. Among AGC, neoplasms with diffuse and strong TIMP-2 staining have less frequent metastasis (28.6%) than cases with focal and weak (68.8%) (p<0.05). Early gastric cancer revealed diffuse and strong TIMP-2 expressions. We conclude that clinical outcome such as depth of invasion or metastasis is more closely related to the expression of TIMP-2 than the corresponding MMPs.