Expression of p53, bcl-2, E-cadherin, matrix metalloproteinase-9, and tissue inhibitor of metalloproteinases-1 in paired primary tumors and brain metastasis.

The objectives of this study were to: (a) characterize the immunohistochemical expression of p53, bcl-2, E-cadherin (EC), matrix metalloproteinase-9 (MMP-9), and tissue inhibitor of metalloproteinases-1 (TIMP-1) in brain metastases; (b) compare immunohistochemical (IHC) expression of brain metastases with their primary tumors; and (c) assess the prognostic value of expression of these markers. Tumors from 35 patients with brain metastasis were studied for IHC expression of p53, bcl-2, EC, MMP-9, and TIMP-1. In 17 cases, primary tumors were also available for study. In brain metastases, p53 was positive in 91% of cases and intermediate in 9%, MMP-9 was positive in all cases, TIMP-1 was intermediate in 6% and negative in 94% of cases, EC expression was positive in 86% of cases and intermediate in 14%, and bcl-2 was variable. All primary tumors were positive for p53 and MMP-9, 3% were intermediate for TIMP-1 and 97% were negative, 65% were positive for EC and 35% were intermediate, whereas bcl-2 expression was variable. Neither p53, bcl-2, TIMP-1, or EC staining correlated with overall survival or survival with brain metastases. No assessment of survival differences could be made for MMP-9 because of its overexpression in all tissues. This study found that MMP-9 and p53 were markedly overexpressed in primary tumors and matched brain metastasis, TIMP-1 expression was negative in the majority of specimens, whereas EC expression was maintained in both primary tumors and brain metastases and bcl-2 expression was variable. This study suggests that the functional balance of MMP-9 and TIMP-1 is shifted toward extracellular matrix degradation in brain metastases and that deregulation of cell cycle control by p53 also exists in brain metastases. The high expression of EC may indicate the importance of adherence at late stages of metastasis but requires further study.