Expression of messenger RNAs for metalloproteinases 2 and 9, type IV collagen, and laminin in nonneoplastic and neoplastic endometrium

In this study, we analyzed the messenger RNA (mRNA) synthesis of matrix metalloproteinases (MMPs) 2 and 9, and their main substrates laminin and type IV collagen by in situ hybridization in nonneoplastic, hyperplastic, and neoplastic endometrial tissues. In nonneoplastic endometrium stromal synthesis of MMP2, laminin and type IV collagen messenger RNA (mRNA) could be detected throughout the cycle. Their synthesis was strongest in the late secretory and decidualized endometrium. In epithelial cells, only laminin mRNA synthesis was observed. MMP9 mRNA was expressed in only stromal and epithelial cells of the decidualized endometrium. In hyperplastic and neoplastic endometrium, the expression of MMP2, MMP9, laminin, and type IV collagen mRNA was variably present in stromal cells, whereas epithelial cells expressed only laminin mRNA, except for one case of a grade III carcinoma, which also showed signals for MMP2 and MMP9 mRNAs in the carcinoma cells. The presence of MMP2, laminin, and IV collagen mRNA in normal endometrium reflects their importance in the tissue response and matrix remodeling during the proliferative and secretory phases of the menstrual cycle. Their mRNA synthesis follows a similar pattern, suggesting that it is associated with hormonal changes during the menstrual cycle. According to the results, MMP9 does not participate in tissue remodeling during the secretory or proliferative phases, but like MMP2, it is found in the neoplastic endometrial stroma, suggesting that it contributes to the invasion of malignant endometrial cells.