RESUMO
<p><b>OBJECTIVE</b>To study the effects of aromatase on breast cancer proliferation and invasive ability, so as to detect the relationship between in situ estrogen levels and molecular biological characteristics of breast cancer.</p><p><b>METHODS</b>By immunohistochemistry staining, the expression of aromatase, matrix metalloproteinases 2 (MMP2) and matrix metalloproteinases (MMP 9) in the primary breast cancers were detected, the associations between aromatase and MMPs as well as clinical-pathological factors were analyzed.</p><p><b>RESULTS</b>The positive rates of aromatase were 25.0% (+) and 29.9% (++). Aromatase status was associated with MMP2, MMP9 and co-expression of MMP2 and MMP9 (P < 0.05), but not associated with tumor size, ER/PR status, menopausal status and tumor grade (P > 0.05). In the postmenopausal patients there was a relationship between aromatase and tumor size (P < 0.05), but not in the premenopausal patients (P > 0.05); there was a relationship between aromatase and co-expression of MMP2/MMP9 in the patients with ER and/or PR positive (P < 0.05), but not in the patients with ER and PR negative (P > 0.05).</p><p><b>CONCLUSIONS</b>In the breast cancer in situ estrogen produced by tumor aromatase may promote the cancer cells proliferation and invasiveness and maybe through ER pathway especially in the postmenopausal patients.</p>