Mammary-specific expression

Inverse Relationship between Protease Inhibitors and Metastatic Ability. All proteases, apart from possibly CD, appear to be controlled by endogenous inhibitors. In theory, therefore, the ability of malignant cells to produce metastasis could depend not only on the levels of the specific protease, but also on the concentration of relevant endogenous inhibitors. Thus, the presence of high levels of protease inhibitors might inhibit metastasis, while low levels of inhibitors might enhance metastasis. An inverse relationship between a number of specific inhibitors and metastatic potential has now been shown. Some examples of this type of relationship include TIMP-1 in Swiss 3T3 cells (K4), cysteine protease inhibitors in mouse melanoma cells (R6), and an alpha-1-proteinase inhibitor in rat mammary carcinomas (N2). Furthermore, a newly described serine protease inhibitor, known as maspin, was found to be expressed less frequently in advanced human breast cancers compared with early cancers (Z2). 

W. Zschiesche, B. Binas, C. Juergensen, and F. Theuring. 2000. Mammary gland specific h EG F receptor transgene expression induces neoplasia and inhibits differentiation. Oncogene 19 2129-2137. 

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