MATRIX METALLOPROTEINASE-7 EXPRESSION IN GASTRIC-CARCINOMA

Background/Aims-Matrix metalloproteinase-7 (MMP-7) belongs to the same family as matrix degrading metalloproteinase (MMPs) that may play an important part in cancer cell invasion and metastasis. This study repo rts on the MMP-7 mRNA expression level both in human gastric carcinoma s and the normal gastric mucosa.Methods-From fresh specimens of 47 sur gical pairs of primary gastric carcinomas and corresponding normal tis sue specimens, cDNA was obtained by reverse transcription (RT) and the reafter MMP-7 mRNAs were detected by means of a polymerase chain react ion. The tumour/normal (T/N) ratio of MMP-7 expression was calculated after correcting for glyceraldehyde-3-phosphate dehydrogenase as an in ternal control. Results-The expression corrected levels of MMP-7 mRNA of the tumour was greater than that of the normal mucosa in 41 of 47 c ases (87%). The 13 cases whose T/N ratio was more than 2.1 showed a de eper invasion of the gastric wall, and more frequent lymphatic or vasc ular permeations than the 34 cases whose T/N ratio was less than 2.0. An immunohistochemical study showed that MMP-7 was predominantly expre ssed in the cancer cells, weakly expressed in normal epithelial cells, and not expressed in the surrounding stromal cells. Conclusions-These findings suggest that the overexpression of MMP-7 may thus play an im portant part in tumour invasion in gastric carcinomas while, in additi on, MMP-7 may also prove to be a useful marker for determining the bio logical aggressiveness of gastric carcinoma.