Quantification of tissue inhibitor of metalloproteinases 2 in plasma from healthy donors and cancer patients

Tissue inhibitor of metalloproteinases (TIMP)-2 is a highly conserved molecule, which binds both active and latent matrix metalloproteinase (MMP)-2. TIMP-2 is also involved in the activation of MMP-2 on the cell surface. A quantitative enzyme-linked immunosorbent assay (ELISA) was established and optimized for measurement of TIMP-2 in plasma. The capturing antibody in the ELISA was a monoclonal, while the detecting antibody was a chicken polyclonal antibody recognizing the native form of human TIMP-2. The levels of TIMP-2 were measured in ethylenediaminetetraacetic acid (EDTA) and citrate plasma from healthy donors. The median values were determined as 163 ng/ml (n = 186) with a range of 109-253 ng/ml for EDTA plasma and 139 ng/ml (n = 77) with a range of 95-223 ng/ml for citrate plasma. The TIMP-2 concentration in citrate plasma from 15 patients with advanced, stage IV breast cancer had a median value of 160 ng/ml, only slightly higher but statistically distinguishable from the level found in citrate plasma from the healthy donors. In addition, the TIMP-2 concentration in EDTA plasma from colorectal cancer patients revealed a significantly higher level in plasma from patients with Dukes stage A (P = 0.01) compared with patients with more advanced Dukes stages.