Expression of matrix metalloproteinase 9 in primary and recurrent breast carcinomas

The matrix metalloproteinases (MMPs) comprise a family of zinc-dependent endopeptidases that are secreted as inactive precursors, which are activated by cleavage of an N-terminal pro-peptide. Their basic mechanisms of action include cancer cell growth, differentiation, apoptosis, migration and invasion, and the regulation of tumour angiogenesis and immune surveillance. The expression of MMP2 and MMP9 has been associated with high potential of metastasis in several human carcinomas including breast cancer. The 29 female patients, 9 premenopausal and 20 postmenopausal, aged from 37 to 79 years were included in this study. Tissue samples were examined in 29 primary and 48 recurrent carcinomas using the tissue microarrays which included 102 cores of primary breast carcinomas and 96 of recurrent breast carcinomas. Immunohistochemistry determined a pattern of expression for MMP9. The staining was diffuse cytoplasmic, strong, moderate, faint/weak and negative. The majority of the breast carcinomas stained homogenously for MMP9 on tumor cells. Statistically significant correlation was found for the expression of MMP9 between primary and recurrent breast carcinomas in general (p < 0.001) and in tumors that were grouped as recurrence before (p = 0.039) and after 24 months (p < 0.001). Strong expression of MMP9 was observed in primary tumors that recurred after 24 months, median: 162.5 (score range 0-300) and those tumors that recurred before 24 months of the initial diagnosis, median: 102.5 (score range 0-250) (p = 0.026).