CBM-07SERUM NSE, MMP-9 AND HER2 ARE PREDICTIVE OF BRAIN METASTASES IN METASTATIC BREAST CANCER PATIENTS

Abstract

BACKGROUND: Breast cancer (BC) is the second leading cause of brain metastases (BM). Predictive factors for BM have been widely studied in metastatic BC; however, there is no known serum tumor marker to accurately predict BM in this population. Serum levels of protein S100, an astrocytic marker, are associated with stroke severity. Neuron Specific Enolase (NSE), a neuronal marker, has been associated with BM prognosis in lung cancer. Elevated serum levels of these markers could reflect the brain damages induced by BM. Matrix Metalloproteinase 9 (MMP-9) is involved in tumor invasion and metastatic dissemination, including BM. Finally, it has been shown that HER2-amplified breast tumors have a particular tropism for central nervous system. This study evaluates the predictive value of these four markers for BM in a population of metastatic BC patients. METHODS: In this case-control study, 88 consecutive BC patients with BM (cases) treated at the Montpellier Cancer Institute (2008-2015) were retrospectively selected, based on the availability of frozen serum samples for tumor markers determination. Cases were matched by age, tumor biology and number of previous metastatic treatment lines to 162 patients with metastatic BC but without CNS involvement (controls). RESULTS: Serum HER2, NSE and MMP-9 levels were significantly higher in cases than in controls (p= 0.0057, p = 0.0051 and p = 0.0062, respectively). Median HER2 (ng/ml) was 21.1 in cases compared to 12.3 in controls; median NSE (µg/l) was 10.8 compared to 8.70 in controls; median MMP-9 (ng/µl) was 422.9 in cases compared to 320.5 in controls. In multivariate analysis, serum HER2 and MMP-9 levels accurately discriminated cases from controls: odd ratio 4.4 (p = 0.000; 95%CI 1.9-9.6) for HER2 and 3.5 (p = 0.005; 95%CI 1.5-8.4) for MMP-9. CONCLUSIONS: Serum HER2 and MMP-9 seem to be predictive of BM in metastatic BC patients. These results need to be validated in further larger prospective studies.