ABSTRACT
Maspin may offer a unique opportunity to block tumor invasion and metastasis. Maspin expression correlates with normality, and pre-malignant and/or less invasive lesions in breast, prostate and oral squamous cells. 1' 5 Therefore, maspin may be a useful molecular marker for the diagnosis and/or prognosis of cancer. Furthermore, accumulated evidence supports a tumor suppressive role of maspin, at the level of invasion and metastasis. For example, orthotopic explants of mammary carcinoma cells transfected with maspin coding cDNA are inhibited in tumor growth and metastasis in nude mouse experiments. 1 These maspin transfectants are significantly inhibited in in vitro invasion and motility assays. 1,6 Consistently, three forms of recombinant human maspin proteins produced in the bacterium E. co li, yeast S. cerevisiae, and baculo-virus infected insect cells Sf9, respectively, exhibit potent inhibitory effects on the invasion and motility of an array of human mammary and prostatic carcinoma cell lines in vitro.7,8 Treatment of human mammary carcinoma cells with maspin leads to a partial restoration of benign epithelial morphology and an increased cell adhesion to fibronectin. 9 Recently, Zhang et al showed that recombinant mouse maspin inhibits the metastasis of human prostate tumor xenografts in nude mice. 10 These data suggest a potential clinical application of maspin in cancer intervention.
