Matrix metalloproteinase-2 (MMP-2) is important in the dissemination and invasion of
tumor cells and activates angiogenesis. We present an immunocytochemical study of MMP-2 expression in circulating prostate cells (CPCs), disseminated
tumor cells (DTCs), and
micrometastasis (mM) in bone marrow of men with
prostate cancer. Methods and Patients.
Tumor cells were identified with anti-PSA immunocytochemistry. Positive samples underwent processing with anti-MMP-2, its expression was compared with Gleason score, concordance of expression, and metastatic and nonmetastatic disease. Results. 215 men participated, CPCs were detected in 62.7%, DTCs in 62.2%, and mM in 71.4% in nonmetastatic
cancer; in metastatic
cancer all had CPCs, DTCs, and mM detected. All CPCs and DTCs expressed
MMP-2; in mM MMP-2 expression was positively associated with increasing Gleason score. MMP-2 expression in CPCs and DTCs showed concordance. In low grade
tumors, mM and surrounding stromal cells were MMP-2 negative, with variable expression in high grade
tumors; in metastatic disease, both mM and stromal cells were MMP-2 positive. Conclusions. CPCs and DTCs are different from mM, with inhibition of MMP-2 expression in mM of low grade
tumors. With
disease progression, MMP-2 expression increases in both mM and surrounding stromal cells, with implications for the use of
bisphosphonates or MMP-2 inhibitors.