Objective: To examine the expression pattern of membrane type-1 matrix metalloproteinase (MT1-MMP) in breast carcinomas.
Methods: Forty-three breast cancer tissues were collected and examined for MT1-MMP protein and mRNA expressions using immunohistochemistry, semi-quantitative RT-PCR and in situ hybridization.
Results: Immunohistochemistry of the breast cancer specimens showed MT1-MMP immunoreactivity on the cancer cell membrane. MT1-MMP mRNA was located in the stromal cells surrounding the breast cancer nest as shown by in situ hybridization. MT1-MMP mRNA expression was detected in all of the carcinomas, but its level was significantly lower in immunohistochemically negative specimens than in positive ones (0.547=0.0886 vs 0.759=0.0802, Plt;0.01).
Conclusion: MT1-MMP is very likely produced by stromal cells surrounding the breast cancer nest and anchored on the cell membrane after activation.