S100β as a predictor of brain metastases

Abstract

BACKGROUNDThe identification of brain metastases in patients with malignant disease has important implications for determining their treatment and prognosis. Asymptomatic metastatic brain tumors may be detected by surveillance imaging techniques, but longitudinal follow‐up of patients who are at risk is sporadic primarily due to cost. Because the development of brain metastases is accompanied and detected by extravasation of contrast agents across the blood‐brain barrier (BBB), the authors hypothesized that peripheral analysis of the BBB indicator S100β may be useful as a screening tool for brain metastases in patients who have no neurologic symptoms.METHODSThirty‐eight patients were enrolled for the current study. All patients had newly diagnosed lung carcinoma and had no neurologic symptoms or known history of brain metastasis. Patients underwent an initial magnetic resonance imaging (MRI) scans and S100β blood tests. S100β tests were repeated in a subset of patients at the time of routine follow‐up MRI scans.RESULTSBased on imaging studies and on serum S100β analyses, the patients were divided in 3 categories: 1) patients with normal S100β levels (0.08 ± 0.02 μg/L; n = 22 patients) and normal MRI scans; 2) patients with elevated S100β levels (0.5 ± 0.28 μg/L; n = 8 patients) and pronounced microvascular changes on MRI scans but with no metastases; and 3) patients with elevated S100β levels (0.28 ± 0.19 μg/L; n = 7 patients) and metastatic brain tumor(s) on MRI scans.CONCLUSIONSBecause of the significant overlap in S100β levels between patients with cerebral microvascular diseases and patients with brain metastases, the authors concluded that the serum S100β level may be used as a surveillance tool to predict or detect brain metastases if appropriate prescreening radiologic tests are obtained and if patients who are candidates for false‐positive results are identified and excluded. Cancer 2005. © 2005 American Cancer Society.

Improving the clinical management of traumatic brain injury through the pharmacokinetic modeling of peripheral blood biomarkers

“…After maximal BBBD, newborns presented a more dramatic increase in serum S100B concentrations. The horizontal dashed lines in ( a ) show a consistency between the observed levels and results from prior literature, for steady-state as well as maximal BBBD in adults [3, 24, 40]. Figure b and c show the behavior for serum levels of the homodimeric form of S100B (21 kD), as well as GFAP (26 kD) and S100B monomer.…”

“…To our knowledge, data on UCHL-1 and GFAP levels in healthy newborns are not available, so we instead used S100B values which have been reported to decrease from an average of 0.9 to 0.3 ng/ml in the first postnatal months and further decrease to 0.11 ng/ml in adolescence [23]. For healthy adults, S100B levels in serum are below 0.1–0.12 ng/ml [3, 24, 25]. Of the physiological variables that may contribute to different biomarker concentrations between newborns and adults, we focused on three possible, non-mutually exclusive factors: (1) GFR is significantly lower in the neonatal stage of development, and does not reach fully mature levels until after infancy; (2) body size, and specifically the ratio of brain volume to volemia/body weight, is dramatically increased in babies; and (3) homeostatic BBB function may differ post-gestation compared to adulthood.…”

Is Peripheral Immunity Regulated by Blood-Brain Barrier Permeability Changes?

“…S100B has been used for many years as a reporter of blood-brain barrier dysfunction [19], [55] or in other studies as a marker of brain damage [67], [68]. Once secreted/released, S100B exerts autocrine and paracrine effects on responsive cells by engaging the receptor for advanced glycation end products [69].…”

The Role of Blood-Brain Barrier Studies in the Pharmaceutical Industry

“…The availability of specific and sensitive clinical markers for BBB functionality would greatly help to assess and interpret possible CNS side effects of the compound which involve the brain vasculature. For instance, the protein S100ß is being examined as a possible marker for BBB opening [242][243][244]325], although its sensitivity and specificity profile appears to be poor.…”