Predicting brain metastases of breast cancer based on serum S100B and serum HER2

Abstract

Brain metastases are a major cause of morbidity and mortality in breast cancer. The aim of the current study was to evaluate the prediction of brain metastases based on serum S100B and human epidermal growth factor receptor 2 (HER2). A total of 107 breast cancer patients were included in the current study from two prospective cohort studies with either elevated serum HER2 levels >15 ng/ml or brain metastases verified by magnetic resonance imaging (MRI) or computer tomography (CT). Following the exclusion of six patients, the remaining 101 patients were divided into two groups: Group 0 (n=55), patients with normal MRI results; and group 1 (n=46), patients with brain metastases. The levels of serum S100B and HER2 in the two groups were analyzed prior to MRI or CT of the brain, and no significant differences were identified in the serum HER2 (P=0.060) or S100B levels (P=0.623) between the groups. The univariate analysis of prognostic factors for brain metastases showed a significant correlation with systemic disease (P<0.001), axillary lymph node metastases (P=0.001) and serum HER2 >30 ng/ml (P=0.002). Only systemic disease (P<0.001) remained statistically significant in the multivariate analysis. In conclusion, serum levels of S100B and HER2 did not predict the risk of brain metastases. In the multivariate analysis, brain metastases were only found to correlate with systemic disease. However, in the univariate analysis, serum HER2 levels >30 ng/ml were identified to correlate with increased risk of brain metastases, which calls for further investigation.

Keywords: HER2/neu; brain metastases; breast cancer; serum S100B; serum human epidermal growth factor receptor 2.

Figure 1

Diagram outlining the exclusion of patients. HER2-MR included 66 patients who underwent brain MRI due to elevated serum HER2 levels >15 ng/ml. TL-VSL-BM included 41 patients treated with radiotherapy for MRI- or CT- verified brain metastases. HER2, human epidermal growth factor receptor 2; MRI, magnetic resonance imaging; CT, computed tomography; DCIS, ductal carcinoma in situ.

Figure 2

Correlation between serum HER2 and S100B (HER2-MR, n=63; TL-VSL-BM, n=38; cut-off, 0.120 μg/l).

Figure 3

Correlation between (A) serum S100B and meningeal and/or brain metastases and (B) serum S100B and brain metastases ≥20 mm. Medians are presented as purple and yellow.