Expression of matrix metalloproteinases (MMP-2 and -9) and their inhibitors (TIMP-1 and -2) in prostate cancer tissue

Matrix metalloproteinases (MMPs) have been implicated in progression and metastases of different tumours. The balance between the MMPs and their natural inhibitors (tissue inhibitors of matrix metalloproteinases; TIMP) seems to be an important factor related to this role. Here, the expression of MMP-2 and -9 along with TIMP-1 and -2 was examined in prostate cancer tissue. A total of 40 radical prostatectomy specimens were embedded in paraffin and immunohistochemical staining was performed to detect MMP-2 and -9, and TIMP-1 and -2. The immunoreactivity was assessed semiquantitively using routine light microscopy. The intensity of staining was correlated to preoperative PSA, T category, Gleason score and clinical parameters of the specimens. The imbalance of MMPs and TIMPs was recognised as a significant loss of TIMP-1 in malignant epithelium and an upregulation of MMPs. Palpable tumours (T2, T3) expressed significantly more MMP-2 and significantly less MMP-9 than T1c tumours. Our data are in accordance with other literature reports in that an imbalance of MMPs and TIMPs is found in malignant tumours. The observed imbalance of MMP and TIMP is mainly caused by a loss of TIMP-1. Furthermore, palpable tumours demonstrated significantly more MMP-2 and significantly less MMP-9 expression than nonpalpable tumours.