Induction of matrix metalloprotease-7 is common in mucinous ovarian tumorsincluding early stage disease

Matrix metalloproteases are known to play an important role in tumor invasi on by mediating degradation of the extracellular matrix. In this study, we have investigated the immunohistochemical expression of matrix metalloprote ase -7 (MMP-7) in 44 mucinous ovarian tumors (9 adenomas, 13 low malignant potential tumors, 22 adenocarcinomas) and 6 normal ovaries. Positive staini ng of MMP-7 is observed in all mucinous ovarian tumors, whereas little or n o staining was observed in surface epithelium as well as the epithelial cel ls of germinal inclusion cyst of the normal ovary. Positive immunostaining of MMP-7 is also observed in the secreted mucin in the tumor glands, which suggests the secretion of the MMP-7 protein from tumor cells. mRNA expressi on of MMP-7 was confirmed using RT-PCR. The MMP-7 gene wars amplified in pa rallel with an internal control gene beta-tubulin using a thermal cycler. m RNA expression levels of MMP-7 were significantly elevated in mucinous tumo r samples compared with that in normal ovaries. Our results suggest that MM P-7 is frequently overexpressed in mucinous ovarian tumors and secreted wit h the mucin which is produced from the tumor cells. MMP-7 may therefore con tribute to mucinous ovarian tumor development or enhanced growth capacity o f mucinous ovarian tumors. MMP-7 may also serve as a target for therapeutic intervention in the down regulation of tumor progression.