S-100beta protein--serum levels in children with brain neoplasms and its potential as a tumor marker

The Role of the S100 Protein Family in Glioma

The S100 protein family consists of 25 members and share a common structure defined in part by the Ca²⁺ binding EF-hand motif. Multiple members' dysregulated expression is associated with progression, diagnosis and prognosis in a broad range of diseases, especially in tumors. They could exert wide range of functions both in intracellular and extracellular, including cell proliferation, cell differentiation, cell motility, enzyme activities, immune responses, cytoskeleton dynamics, Ca²⁺ homeostasis and angiogenesis. Gliomas are the most prevalent primary tumors of the brain and spinal cord with multiple subtypes that are diagnosed and classified based on histopathology. Up to now the role of several S100 proteins in gliomas have been explored. S100A8, S100A9 and S100B were highly expression in serum and may present as a marker correlated with survival and prognosis of glioma patients. Individual member was confirmed as a new regulator of glioma stem cells (GSCs) and a mediator of mesenchymal transition in glioblastoma (GBM). Additionally, several members up- or downregulation have been reported to involve in the development of glioma by interacting with signaling pathways and target proteins. Here we detail S100 proteins that are associated with glioma, and discuss their potential effects on progression, diagnosis and prognosis.

Prognostic value of the S100B protein in newly diagnosed and recurrent glioma patients: a serial analysis

The S100B protein is associated with brain damage and a breached blood–brain barrier. A previous pilot study showed that high serum levels of S100B are associated with shorter survival in glioma patients. The aim of our study was to assess the prognostic value in terms of survival and longitudinal dynamics of serum S100B for patients with newly diagnosed and recurrent glioma. We obtained blood samples from patients with newly diagnosed and recurrent glioma before the start (baseline) and at fixed time-points during temozolomide chemotherapy. S100B-data were dichotomized according to the upper limit of the reference value of 0.1 μg/L. Overall survival (OS) was estimated with Kaplan–Meier curves and groups were compared with the log rank analysis. To correct for potential confounders a Cox regression analysis was used. We included 86 patients with newly-diagnosed and 27 patients with recurrent glioma. Most patients in both groups had baseline serum levels within normal limits. In the newly diagnosed patients we found no significant difference in OS between the group of patients with S100B levels >0.1 μg/L at baseline compared to those with <0.1 μg/L. In the patients with recurrent glioma we found a significantly shorter OS for patients with raised levels. In both groups, S100B values did not change significantly throughout the course of the disease. Serum S100B levels do not seem to have prognostic value in newly diagnosed glioma patients. In recurrent glioma patients S100B might be of value in terms of prognostication of survival.

Elevated blood markers 1 year before manifestation of malignant glioma

We detected distinct plasma concentration profiles of S100B, neuropeptide Y, and secretagogin in 3 of 191 patients enrolled in a previous study investigating brain-tissue-related markers in the blood of patients with atrial fibrillation. Intriguingly, 2 of these 3 patients, both of whom were without neurological symptoms at the time of blood sampling, were diagnosed with malignant glioma (MG) approximately 1 year later. To our knowledge, this is the first report indicating that distinct blood biomarker profiles may be detected long before clinical manifestation of MG.

Serum levels of glial fibrillary acidic protein correlate to tumour volume of high-grade gliomas

OBJECTIVES

To investigate serum levels of glial fibrillary acidic protein (GFAP) and S-100B in patients with newly diagnosed high-grade gliomas.

MATERIALS AND METHODS

GFAP and S-100B were measured by enzyme-linked immunosorbent assay techniques in preoperative serum from 31 patients with high-grade gliomas. A database with clinical, radiological and histological variables was created for statistical analyses.

RESULTS

Mean serum levels of 239 ng/l (range 30-1210 ng/l) for GFAP and 58.3 ng/l (range 22-128 ng/l) for S-100B were found. Of the 31 patients, 16 had elevated levels of GFAP while only two showed increased S-100B concentrations. Tumour size was the only variable significantly associated with serum levels of GFAP (P < 0.0001) with a linear correlation coefficient of 0.67.

CONCLUSIONS

Serum levels of GFAP demonstrated a linear correlation to tumour volume in patients with high-grade gliomas. GFAP seems to be a more reliable biomarker in patients with high-grade gliomas than the commercially available S-100B.

Secretagogin expression in tumours of the human brain and its coverings

Secretagogin is a recently described calcium-binding protein, which is expressed in some neurons of the human brain. In this study we systematically investigated secretagogin expression in 245 tumours of the human brain and its coverings using immunohistochemistry. We found focal or widespread secretagogin expression in tumour cells in 1/18 oligoastrocytomas, 1/19 oligodendrogliomas, 2/20 anaplastic oligodendrogliomas, 2/9 ependymomas, 2/11 anaplastic ependymomas, 2/10 glioblastomas, 3/11 gangliogliomas and 1/2 anaplastic gangliogliomas, 10/10 central neurocytomas, 5/10 classic medulloblastomas, 4/5 desmoplastic medulloblastomas, 3/5 large cell/anaplastic medulloblastomas, 3/5 neuroblastomas, 3/10 meningiomas, 2/10 haemangioblastomas, and 13/19 pituitary adenomas. Further, we observed secretagogin expression in endothelial cells in 5/10 meningiomas, 2/5 haemangiopericytomas, and 2/10 haemangioblastomas. We detected no secretagogin expression in fibrillary astrocytoma, pilocytic astrocytoma, DNT, pineocytoma, pineoblastoma, subependymal giant cell astrocytoma (SEGA), atypical teratoid/rhabdoid tumour (AT/RT), or primary central nervous system lymphoma (PCNSL). We conclude that secretagogin is differentially expressed in human neuronal, glial, and embryonal brain tumours, meningial neoplasms and pituitary adenomas. Our findings indicate that secretagogin is involved in the calcium metabolism of tumour cells and endothelial cells in a subset of neoplasms of the brain and its coverings. Anti-secretagogin immunohistochemistry does not seem to be helpful in most differential diagnostic situations in surgical neuropathology.

S100A13, a new marker of angiogenesis in human astrocytic gliomas

S100 proteins are Ca(2+)-binding polypeptides involved in the tumourigenesis of several human neoplasms. S100A13 is a key regulator of the stress-dependent release of FGF1, the prototype of the FGF protein family involved in angiogenesis. Indeed, S100A13 is a copper binding protein able to enhance the export of FGF1 in response to stress in vitro and to induce the formation of a multiprotein aggregate responsible for FGF1 release. We investigated the expression of S100A13 in human astrocytic gliomas in relation to tumour grading and vascularization. A series of 26 astrocytic gliomas was studied to evaluate microvessel density and to assess FGF1, S100A13 and VEGF-A expression. FGF1 was equally expressed in the vast majority of tumours, whereas S100A13 and VEGF-A were significantly up-regulated in high-grade vascularized gliomas. Moreover, both S100A13 and VEGF-A expression significantly correlated with microvessel density and tumour grading. These data suggest that the up-regulation of S100A13 and VEGF-A expression correlates with the activation of angiogenesis in high-grade human astrocytic gliomas.