Abstract P4-07-04: Preoperative Plasma Concentration of MMP-9/TIMP-1 Complexes Is Not Associated with Disease Outcome in Primary Breast Cancer (N=483)

Abstract

Abstract Background: Plasma levels of Tissue Inhibitor of Metalloproteinases-1 (TIMP-1) have been reported as predictors of poor prognosis. Indeed, in a previous study of 519 primary breast cancer patients we reported that high levels of TIMP-1 were associated with a poor prognosis (Würtz et al, 2008). In our previous study we quantified total levels of TIMP-1 in plasma; however, TIMP-1 is present in plasma in a non-complexed form and bound to various proteins. Thus, studying the different fractions might refine prognostic stratification and provide further insight into the role of TIMP-1 in tumor biology. Matrix Metalloproteinase-9 (MMP-9) is an important TIMP-1 binding partner and MMP-9 has previously been suggested as a breast cancer biomarker (Li et al, 2004; Somiari et al, 2006). Aim: The aim of the study was to analyze the concentration of MMP-9/TIMP-1 complexes in plasma from our previously studied primary breast cancer patients and evaluate whether these levels are associated with disease outcome. Materials and methods: Plasma concentrations of MMP-9/TIMP-1 complexes were measured using the human MMP-9/TIMP-1 Complex DuoSet® ELISA Development System (R&D Systems, Inc.) The ELISA was thoroughly validated for measurements of MMP-9/TIMP-1 complexes in EDTA plasma. Samples included preoperatively obtained EDTA plasma from consecutively enrolled patients with primary breast cancer. Of the previously studied 519 patients, 483 had plasma samples available for analysis and follow-up data registered by the Danish Breast Cancer Cooperative Group and were included in the present study. The median follow-up time was 5.1 years. The relationship between MMP-9/TIMP-1 complexes and classical prognostic parameters was analyzed and the association with recurrence-free survival (RFS; includes breast cancer relapse, contralateral breast cancer, other malignant disease, and death without a previous relapse) was studied. Results: The ELISA was validated with acceptable results. The median TIMP-1 concentration was 2.06 ng/mL. For analysis, patients were grouped in quartiles of increasing MMP-9/TIMP-1 plasma concentrations. MMP-9/TIMP-1 complex levels were associated with menopausal status and with hormone receptor status; no significant associations with other clinico-pathological parameters (tumor size, nodal status, malignancy grade, age) were found. No statistically significant difference in survival was observed among TIMP-1 high and low groups (quartiles, log-rank analysis p=0.96). In a Cox multivariable analysis (including tumor size, nodal status, hormone receptor status, malignancy grade, menopausal status, age), only age (> 70 years) and hormone receptor status contributed significantly to the model for RFS (P<0.001). MMP-9/TIMP-1 complex concentration was not associated with RFS in this model. Conclusions: In this group of primary breast cancer patients we did notfind any association between MMP-9/TIMP-1 complex levels in plasma and RFS. Total TIMP-1 levels have previously been shown to correlate with prognosis in this patient cohort. Accordingly, our current results point to other TIMP-1 fractions, i.e. the fraction of free TIMP-1 or TIMP-1 in complex with other plasma proteins, as potential indicators of poor prognosis. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P4-07-04.