Background: Matrix metalloproteinase-7 (MMP-7) is a member of the family of matrix-degrading metalloproteinases (MMPs) that are considered to contribute to cancer invasion and metastasis. One of the gene products that the authors have isolated by a cDNA subtraction of human gastric cancer minus normal gastric mucosa is MMP-7. The purpose of this study was to examine the expression of MMP-7 mRNA in different stages of human colorectal carcinomas.
Methods: A subtracted complementary DNA library was generated from a paired sample of human gastric carcinoma minus normal gastric mucosa. Screening of the library clones determined that MMP-7 mRNA was overexpressed. The complementary DNA insert was then used as a probe to evaluate the expression in a larger number of surgical samples of human colorectal carcinomas by Northern hybridization.
Results: The mRNA signal was greater in the colorectal carcinoma than in paired adjacent normal colonic or rectal mucosa in 39 of 47 cases. The expression of MMP-7 mRNA in tumor tissues increased with increasing Dukes' stage (P < 0.05). The MMP-7 mRNA expression was greatest in the metastatic liver lesions.
Conclusions: The findings imply that MMP-7 mRNA is overexpressed in human colorectal carcinomas and that MMP-7 may prove useful as a marker of biologic aggressiveness.