LOCALIZATION BY IN-SITU HYBRIDIZATION OF MESSENGER-RNAS ENCODING STROMELYSIN-3 AND TISSUE INHIBITORS OF METALLO-PROTEINASES TIMP-1 AND TIMP-2 IN HUMAN HEAD AND NECK CARCINOMAS

The presence and distribution of mRNAs encoding a matrix metalloprotei nase (MMP) stromelysin 3 and two tissue inhibitors of MMP, TIMP-1 and TIMP-2 have been studied by in situ hybridization of 18 human epidermo id head and neck carcinomas and four normal tissues. We found that in 16 tumors out of 18, stromelysin 3 mRNAs were only expressed by fibrob lasts which were in close contact to invasive cancer cells. Tumor cell s and normal tissues were not labeled. TIMP-1 mRNAs were detected in w ell differentiated cancer cells and in endothelial cells in all the ca ncers. In 13 out of the 18 carcinomas, TIMP-2 mRNAs were localized in only a few stromal cells near well differentiated invasive cancer cell s and in endothelial cells. The significant expression of TIMP-1 and T IMP-2 mRNAS may lead to less aggressive MMPs, especially in the case o f stromelysin 3, in the invasive process of the stroma.