Tissue inhibitors of matrix metalloproteinases (TIMPs) play an important role in regulating the activity of matrix metalloproteinases (MMPs). Tumour cell invasion and metastasis closely correlate with the activities of two MMPs, MMP2 and MMP9, both of which degrade type IV collagen in basement membranes. TIMPs constitute a family of at least three types of protein of which TIMP1 and TIMP2 are expressed in a wide variety of cell types. Although TIMP1 and TIMP2 inhibit all types of activated MMPs to varying degrees, TIMP2 is known to preferentially inhibit MMP2. TIMP1 and TIMP2 also bind to proMMP9 and proMMP2, respectively, to form stable complexes in which activation of the proenzymes is expressed. Studies have revealed that both TIMP1 and TIMP2 can inhibit the invasive potential of tumour cells in vi tro and their metastatic phenotype in vivo. This antibody may be used to evaluate the invasive nature of some tumour types, eg colorectal carcinomas, and determine the tissue distribution of TIMPs in other tumours such as adenomas and also in normal tissue.