Expression of tissue inhibitor of metalloproteinase-1 and type IV collagenase/gelatinase messenger RNAs in human breast cancer.

The relationship between malignant epithelial cell growth and the formation of tumor stroma is poorly understood. To investigate the roles of type IV collagenases/gelatinases and tissue inhibitor of metalloproteinase-1 (TIMP-1) in human breast cancer, we localized their messenger RNAs (mRNAs) in normal and malignant breast tissue. Type IV collagenase/gelatinase mRNAs were expressed at low levels by some tumor cells. High levels of TIMP-1 mRNA were found in all areas where tissue remodeling was evident, particularly in cells at the tumor-stromal interface. Small blood vessels in both the tumor and stroma were often outlined by high levels of TIMP-1 mRNA. These results indicate that TIMP-1 and type IV collagenases/gelatinases are expressed independently in breast cancer.