S100B protein in clinical diagnostics: assay specificity

Role of Receptor for Advanced Glycation End-Products in Endometrial Cancer: A Review

Endometrial cancer (EC) is the most common gynecological malignancy. EC is associated with metabolic disorders that may promote non-enzymatic glycation and activate the receptor for advanced glycation end-products (RAGE) signaling pathways. Thus, we assumed that RAGE and its ligands may contribute to EC. Of particular interest is the interaction between diaphanous-related formin 1 (Diaph1) and RAGE during the progression of human cancers. Diaph1 is engaged in the proper organization of actin cytoskeletal dynamics, which is crucial in cancer invasion, metastasis, angiogenesis, and axonogenesis. However, the detailed molecular role of RAGE in EC remains uncertain. In this review, we discuss epigenetic factors that may play a key role in the RAGE-dependent endometrial pathology. We propose that DNA methylation may regulate the activity of the RAGE pathway in the uterus. The accumulation of negative external factors, such as hyperglycemia, inflammation, and oxidative stress, may interfere with the DNA methylation process. Therefore, further research should take into account the role of epigenetic mechanisms in EC progression.

Cutaneous Melanomas: A Single Center Experience on the Usage of Immunohistochemistry Applied for the Diagnosis

Cutaneous melanoma (cM) is the deadliest of all primary skin cancers. Its prognosis is strongly influenced by the stage at diagnosis, with early stages having a good prognosis and being potentially treatable with surgery alone; advanced stages display a much worse prognosis, with a high rate of recurrence and metastasis. For this reason, the accurate and early diagnosis of cM is crucial-misdiagnosis may have extremely dangerous consequences for the patient and drastically reduce their chances of survival. Although the histological exam remains the "gold standard" for the diagnosis of cM, a continuously increasing number of immunohistochemical markers that could help in diagnosis, prognostic characterization, and appropriate therapeutical choices are identified every day, with some of them becoming part of routine practice. This review aims to discuss and summarize all the data related to the immunohistochemical analyses that are potentially useful for the diagnosis of cM, thus rendering it easier to appropriately applicate to routine practice. We will discuss these topics, as well as the role of these molecules in the biology of cM and potential impact on diagnosis and treatment, integrating the literature data with the experience of our surgical pathology department.

Interfering with S100B-effector protein interactions for cancer therapy

S100 calcium-binding protein B (S100B) is overexpressed in various malignant tumors, where it regulates cancer cell proliferation and metabolism by physical interactions with other molecules. Interfering with S100B-effector protein interactions is a potential strategy to treat malignant tumors. Although some S100B inhibitors have been discovered by virtual screening (VS), most target the S100B-p53 interaction. Hence, there is scope for the discovery of other S100B-effector protein interaction modulators for malignant tumors. In this review, we provide an overview of S100B-effector protein interaction inhibitor discovery using VS and discuss promising S100B-effector protein interaction targets that permit in silico analysis for drug discovery.

Serum S100B Levels in Melanoma

Malignant melanoma is a cancer with increasing incidence worldwide with relevant socioeconomic impact. Despite progress in prevention and early detection, it is one of the most lethal forms of skin cancer. Therefore it is urgent need to identify suitable biomarkers in order to improve early diagnosis, precise staging, and prognosis, as well as for therapy selection and monitoring. In this book chapter, we are focusing on S100B and discuss its clinical relevance in melanoma.

Ovarian cancer stem cells: What progress have we made?

Ovarian cancer (OvCa) is the most lethal gynecological malignancy in the United States primarily due to lack of a reliable early diagnostic, high incidence of chemo-resistant recurrent disease as well as profuse tumor heterogeneity. Cancer stem cells (CSCs) continue to gain attention, as they are known to resist chemotherapy, self-renew and re-populate the bulk tumor with undifferentiated and differentiated cells. Moreover, CSCs appear to readily adapt to environmental, immunologic and pharmacologic cues. The plasticity and ability to inactivate or activate signaling pathways promoting their longevity has been, and continues to be, the challenge faced in developing successful CSC targeted therapies. Identifying and understanding unique ovarian CSC markers and the pathways they utilize could reveal new therapeutic opportunities that may offer alternative adjuvant treatment options. Herein, we will discuss the current state of ovarian CSC characterization, their contribution to disease resistance, recurrence and shed light on clinical trials that may target the CSC population.

OXYTOCIN REDUCES SEIZURE BURDEN AND HIPPOCAMPAL INJURY IN A RAT MODEL OF PERINATAL ASPHYXIA

CONTEXT

Foetal asphyxia, a frequent birth complication, detrimentally impacts the immature brain, resulting in neuronal damage, uncontrolled seizure activity and long-term neurological deficits. Oxytocin, a neurohormone mediating important materno-foetal interactions and parturition, has been previously suggested to modulate the immature brain's excitability, playing a neuroprotective role. Our aim was to investigate the effects of exogenous oxytocin administration on seizure burden and acute brain injury in a perinatal model of asphyxia in rats.

ANIMALS AND METHODS

Asphyxia was modelled by exposing immature rats to a 90-minute episode of low oxygen (9% O2) and high CO2 (20% CO2). Control rats were kept in ambient room-air for the same time interval. In a third group of experiments, oxytocin (0.02 UI/g body weight) was nasally administered 30 minutes before the asphyxia episode. Seizure burden was assessed by the cumulative number of loss of righting reflex (LRR) over a two-hour postexposure period. Acute brain injury was assessed through hippocampal S-100 beta, a biomarker of cellular injury, 24-hours after exposure.

RESULTS

Asphyxia increased both LRR and hippocampal S-100 beta protein compared to controls, and these effects were significantly reduced by oxytocin administration.

CONCLUSION

Oxytocin treatment decreased both seizure burden and hippocampal injury, supporting a potential neuroprotective role for oxytocin in perinatal asphyxia.

Study of serum levels and skin expression of S100B protein in psoriasis

Background

S100B protein was reported to be elevated in psoriatic patients' serum, with no previous evaluation of its skin expression, in contrast to the extensively studied S100 protein.

Objective

To evaluate the serum level and skin expression of S100B in psoriasis to assess its possible involvement in its pathogenesis.

Methods

Serum level of S100B protein was estimated in 40 psoriatic patients of different clinical varieties and 10 healthy controls. S100B protein expression was assessed immunohistochemically in lesional and non-lesional skin of patients and in normal skin of controls. Relation to disease severity was also evaluated.

Results

Serum level of S100B protein was significantly higher in psoriatic patients (0.15±0.03 µg/l) than in controls (0.03±0.007 µg/l) (P-value <0.001) with no significant correlation with PASI score. On comparing grades of S100B protein skin expression in lesional and non-lesional skin biopsies, a statistically significant difference was found (P=0.046) with higher percentage of strong S100B skin expression (60%) in non-lesional than in lesional (42%) skin. All the control biopsies showed negative expression.

Study limitations

Relatively small sample size with a limited range of low PASI scores.

Conclusion

This study points to a potential link between psoriasis and S100B protein with higher serum and skin expression in patients than in controls.

S100B expression in breast cancer as a predictive marker for cancer metastasis

In the tumor microenvironment, soluble molecules play important role in the establishment of a pre-metastatic niche. The S100 calcium-binding protein family are inflammatory molecules that contribute to the development of a pro-inflammatory tumor microenvironment. S100B belongs to the S100 family and serum S100B (also known as S100beta) serves as a marker for metastasis in lung cancer, ovarian cancer and melanoma. However, the association between S100B and the metastasis of breast cancer is not yet well understood. In the present study, a relatively low S100B expression was observed in the tumor samples compared to normal breast tissue among online microarray datasets. When the estrogen receptor (ER)-negative breast cancer cell lines, MDA-MB-231 and Hs578T, were treated with recombinant human S100B, cell migration was significantly inhibited and epithelial cadherin expression was increased. Our results revealed that a high S100B expression predicted a good overall survival in patients with ER-negative breast cancer, and good distant metastases-free survival in all patients with breast cancer via the analysis of the KM plotter and SurvExpress databases. Although previous studies have indicated that the interaction of S100B with wild-type p53 inhibits p53 function, a high S100B expression is associated with a good prognosis in patients with p53 mutant and p53 wild-type breast cancers. On the whole, our findings demonstrate that S100B treatment suppresses the migratory capacity of ER-negative breast cancer and that S100B expression may serve a predictive marker for metastasis in breast cancer.

Magnetic resonance spectroscopy for assessment of brain injury in the rat model of sepsis

The diagnostic value of magnetic resonance spectroscopy (MRS), T2-weighted imaging (T2WI) and serum markers of brain injury in a rat model of sepsis were investigated. Rats were randomly divided into the control group and 6, 12 and 24 h after lipopolysaccharide-injection groups. Brain morphology and metabolism were assessed with T2WI magnetic resonance imaging (MRI) and MRS. Serum and brain tissue samples were then collected to examine the concentrations of neuron-specific enolase (NSE) and S100-β protein. Brain T2WI showed no differences between the groups. N-acetylaspartate/choline (NAA/Cr) ratio measured by MRS showed different degrees of decrease in the sepsis groups, and serum NSE and S100-β concentrations were increased compared with the control group. Apoptosis rates were measured in the right hippocampal area, and there were statistically significant differences between the indicated groups and the control group (p<0.05). The correlation between apoptosis rate and NAA/Cr ratio was closer than that between apoptosis rate and NSE or S100-β (−0.925 vs. 0.434 vs. 0.517, respectively). In conclusion, MRS is a sensitive, non-invasive method to investigate complications of brain injury in septic rats, which may be utilized for the early diagnosis of brain injury caused by sepsis.

Biomarker value and pitfalls of serum S100B in the follow-up of high-risk melanoma patients

BACKGROUND AND OBJECTIVES

Serum levels of S100B are standard in monitoring advanced malignant melanoma patients in order to discriminate progressive from non-progressive disease. False-positive results lead to distress among patients and increase the amount of cost-intensive diagnostics. We therefore analyzed reported comorbid diseases as putative sources of excessive S100B release.

PATIENTS AND METHODS

Here, we report a single-center experience on serum S100B levels in 2,664 blood samples from 1,113 stage IB to IV melanoma patients (AJCC) who presented for follow-up examinations over a period of 24 months.

RESULTS

Overall, 295 (11%) of patients developed disease progression. In patients with a high tumor load, the rate of false-negative results was 30/185 (16%). The rate of false-positive results was 247/2369 (12%). One hundred and six false-positive results (69%) compared to 46 true-positive results (31%) were found in patients with cardiovascular diseases such as arrhythmia (50/32) or previous myocardial infarction (22/14). Moreover, obesity (85/14), liver cirrhosis (31/10), migraine (18/2), chronic kidney disease (13/2), and previous stroke (11/1) were found to be associated with false-positive S100B levels.

CONCLUSIONS

Serum S100B is a useful quantitative biomarker in routine follow-up of high-risk melanoma patients. While false-negative results are frequent in patients with low tumor load, false-positive results are associated with several comorbid diseases and warrant careful reevaluation.

Biomarkers of Brain Damage and Postoperative Cognitive Disorders in Orthopedic Patients: An Update

The incidence of postoperative cognitive dysfunction (POCD) in orthopedic patients varies from 16% to 45%, although it can be as high as 72%. As a consequence, the hospitalization time of patients who developed POCD was longer, the outcome and quality of life were worsened, and prolonged medical and social assistance were necessary. In this review the short description of such biomarkers of brain damage as the S100B protein, NSE, GFAP, Tau protein, metalloproteinases, ubiquitin C terminal hydrolase, microtubule-associated protein, myelin basic protein, α-II spectrin breakdown products, and microRNA was made. The role of thromboembolic material in the development of cognitive decline was also discussed. Special attention was paid to optimization of surgical and anesthetic procedures in the prevention of postoperative cognitive decline.

S100B blood levels and childhood trauma in adolescent inpatients

BACKGROUND

Serum levels of the astrocytic protein S100B have been reported to indicate disruption of the blood-brain barrier. In this study, we investigated the relationship between S100B levels and childhood trauma in a child psychiatric inpatient unit.

METHOD

Levels of S100B were measured in a group of youth with mood disorders or psychosis with and without history of childhood trauma as well as in healthy controls. Study participants were 93 inpatient adolescents admitted with a diagnosis of psychosis (N = 67), or mood disorder (N = 26) and 22 healthy adolescents with no history of trauma or psychiatric illness. Childhood trauma was documented using the Life Events Checklist (LEC) and Adverse Child Experiences (ACE).

RESULTS

In a multivariate regression model, suicidality scores and trauma were the only two variables which were independently related to serum S100B levels. Patients with greater levels of childhood trauma had significantly higher S100B levels even after controlling for intensity of suicidal ideation. Patients with psychotic diagnoses and mood disorders did not significantly differ in their levels of S100B. Patients exposed to childhood trauma were significantly more likely to have elevated levels of S100B (p < .001) than patients without trauma, and patients with trauma had significantly higher S100B levels (p < .001) when compared to the control group. LEC (p = 0.046), and BPRS-C suicidality scores (p = 0.001) significantly predicted S100B levels.

CONCLUSIONS

Childhood trauma can potentially affect the integrity of the blood-brain barrier as indicated by associated increased S100B levels.

S100 proteins in cancer

In humans, the S100 protein family is composed of 21 members that exhibit a high degree of structural similarity, but are not functionally interchangeable. This family of proteins modulates cellular responses by functioning both as intracellular Ca(2+) sensors and as extracellular factors. Dysregulated expression of multiple members of the S100 family is a common feature of human cancers, with each type of cancer showing a unique S100 protein profile or signature. Emerging in vivo evidence indicates that the biology of most S100 proteins is complex and multifactorial, and that these proteins actively contribute to tumorigenic processes such as cell proliferation, metastasis, angiogenesis and immune evasion. Drug discovery efforts have identified leads for inhibiting several S100 family members, and two of the identified inhibitors have progressed to clinical trials in patients with cancer. This Review highlights new findings regarding the role of S100 family members in cancer diagnosis and treatment, the contribution of S100 signalling to tumour biology, and the discovery and development of S100 inhibitors for treating cancer.

Use of proteins as biomarkers and their role in carcinogenesis

Summary: Improved diagnostic methods and medical therapies are necessary for early detection and treatment and an improved prognosis. It is thus vital to both examine and evaluate the role of the various existing proteins as biomarkers in carcinogenesis and to assess the contribution of these proteins in anti-cancer activity, for consideration in therapeutic strategies. It is essential to both examine and evaluate the role of the various existing proteins as biomarkers in carcinogenesis and to assess the contribution of these proteins in anti-cancer activity, for consideration in therapeutic strategies. The purpose of this review is twofold. Firstly, it is to evaluate recent data about which proteins can be utilized as biomarkers in carcinogenesis. The proteins reviewed include: CPTP, IL-6, CCN, and S100. Secondly, it is to evaluate the contribution of dietary proteins in cancer activity. Specifically, how whey protein, soy proteins and lectin, a phytochemical could be useful in cancer prevention and treatment.

Recent Findings: Whey protein, present in dairy products, is an excellent source of the sulphur amino acid cysteine, the rate limiting substrate in glutathione synthesis. Notably, this protein survives digestion and has been shown to have anti-carcinogenic properties in animal studies. Lectins are phytochemicals present in plant foods, and have active components which alters cancer initiation, promotion and progression. Lectins have been characterized as a useful tool in biochemistry, cell biology, immunology and in diagnostic and therapeutic purposes in cancer research. Soy proteins contain various compounds, including isoflavones, protease inhibitors and protein kinase inhibitors, which have been proven effective in tumor growth inhibition. They have therefore, been greatly emphasized in cancer prevention and treatment. It has been proved that soy food consumption was associated with decreased risk of death and recurrence of breast cancer. CPTP is a recently discovered protein whose main role is to transport C1P, a pro-inflammatory molecule. The discovery of CPTP may shine a light on the mechanism of inflammatory diseases, and hopefully offer a potential target for therapeutic purposes in cancer research. Interleukin-6 is a multifunctional cytokine that affects the activity of cancer cells. It is involved in tumor growth, and elevated levels is associated with an increased risk of cancer. S100B is a well-established biomarker for malignant melanoma, and useful in assessing tumor load, stage and prognosis for patients with this disease. Other members of this family of proteins include S100A4, which has been associated with several malignancies and S100A2, which has been found to be decreased in some cancers. CCN are a group of regulatory proteins, located in the extracellular matrix (maricellular). They are involved in cellular adhesion, mitogenesis, chemotaxis, cell survival, and wound healing. CCN proteins are also able to modulate the signals of several proteins, which may also influence skeletal development and angiogenesis. Many of the functions of these proteins are thus also related to tumor growth. Furthermore, CCN interacts with estrogen in the development of cancer, and is implicated in some breast and ovarian cancers.

Value of melanocytic-associated immunohistochemical markers in the diagnosis of malignant melanoma: a review and update

Since the identification of S100 protein as an immunohistochemical marker that could be useful in the diagnosis of melanoma in the early 1980s, a large number of other melanocytic-associated markers that could potentially be used to assist in the differential diagnosis of these tumors have also been investigated. A great variation exists, however, among these markers, not only in their expression in some subtypes of melanoma, particularly desmoplastic melanoma, but also in their specificity because some of them can also be expressed in nonmelanocytic neoplasms, including various types of soft tissue tumors and carcinomas. This article reviews the information that is currently available on the practical value of some of the markers that have more often been recommended for assisting in the diagnosis of melanomas, including those that have only recently become available.

Potential biomarkers for malignant melanoma

Melanoma is one of the most aggressive cancers and its high metastatic potential has a large impact on the number of melanoma deaths. The pathological diagnosis is still the gold standard for melanoma and immunohistochemistry plays an important role in discriminating between melanomas. Recently, emerging molecular knowledge may lead to further identification of clinically relevant biomarkers, such as S100B, MIA, TA-90IC, 5-S-CD, SPARC, CSPG4, HSP105, IMP3, KIF2A, miR-221, YKL-40, some cancer stem cells (CD133, Nestin, CD166, CD20, CD271) and some monoclonal antibodies (KBA62, PNL2), for malignant melanoma detection, risk stratification and prediction/prognosis. However, all of the current main markers have some shortcomings. For example, all markers have limitations in sensitivity and specificity, even the first-line marker, S100 protein. So, sometimes, many of the classification criteria that have been proposed show considerable overlap, making it difficult to categorize cases reproducibly, based on histopathological criteria alone. Besides that, the increased expression of some proteins in melanomas suggests that there are abnormal proteins synthesized due to the genetic pathway. Therefore, we expect that there will be more instrumental breakthroughs in the abnormal gene field, especially with respect to gene mutation. Ultimately, novel melanoma biomarkers could be found and gradually become targeted treatment strategies for a poor prognosis in advanced melanoma in the near future.

Development of a rapid and high-performance chemiluminescence immunoassay based on magnetic particles for protein S100B in human serum

Protein S100B is a clinically useful non-invasive biomarker for brain cell damage. A rapid chemiluminescence immunoassay (CLIA) for S100B in human serum has been developed. Fluorescein isothiocyanate (FITC) and N-(aminobutyl)-N-(ethylisoluminol) (ABEI) are used to label two different monoclonal antibodies of anti-S100B. Protein S100B in serum combines with labeled antibodies and can form a sandwiched immunoreaction. A simplified separation procedure based on the use of magnetic particles (MPs) that were coated with anti-FITC antibody is performed to remove the unwanted materials. After adding the substrate solution, the relative light unit (RLU) of ABEI is measured and is found to be directly proportional to the concentration of S100B in serum. The relevant variables involved in the CLIA signals are optimized and the parameters of the proposed method are evaluated. The results demonstrate that the method is linear to 25 ng/mL S100B with a detection limit of 0.02 ng/mL. The coefficient of variation (CV) is < 5% and < 6% for intra- and interassay precision, respectively. The average recoveries are between 97 and 107%. The linearity-dilution effect produces a linear correlation coefficient of 0.9988. Compared with the commercial kit, the proposed method shows a correlation of 0.9897. The proposed method displays acceptable performance for quantification of S100B and is appropriate for use in clinical diagnosis.

Protein S100B in Traumatic Brain Injury

Protein S100B is a small calcium-binding protein expressed in astroglial cells in the central nervous system. Its concentration increases in cerebrospinal fluid and blood after traumatic brain injury. There are several commercially available methods for analyzing serum S100B. The clinical use of serum S100B is mainly in minor head injury, as a complement to existing guidelines in order to help clinicians to determine who could safely be discharged without a previous CT scan. S100B in severe TBI is still being studied as a marker for secondary neurological complications, but has not yet had an impact in this specific area. Recent research on the clinical use of S100B in pediatric TBI has shown promising results, and the introduction of S100B in minor head injuries could have even greater impact than for adults. However, more research needs to be done before a biomarker can be clinically used in pediatric TBI.

S100B protein in neurodegenerative disorders

"Classic" neurodegenerative disorders, such as Alzheimer's disease and amyotrophic lateral sclerosis share common pathophysiological features and involve progressive loss of specific neuronal populations, axonal or synaptic loss and dysfunction, reactive astrogliosis, and reduction in myelin. Furthermore, despite the absence of astrogliosis, impaired expression of astrocyte- and oligodendrocyte-related genes has been observed in patients with major psychiatric disorders, including schizophrenia and mood disorders. Because S100B is expressed in astrocytes and oligodendrocytes, its concentration in cerebrospinal fluid (CSF) or serum has been considered a suitable surrogate marker for the diagnostic or prognostic assessment of neurodegeneration. This review summarizes previous postmortem, CSF and serum studies regarding the role of S100B in this context. A general drawback is that only small single-center studies have been performed. Many potential confounding factors exist because of the wide extra-astrocytic and extracerebral expression of S100B. Due to lack of disease specificity, reliance on S100B concentrations for differential diagnostic purposes in cases of suspected neurodegenerative disorders is not recommended. Moreover, there is no consistent evidence for a correlation between disease severity and concentrations of S100B in CSF or serum. Therefore, S100B has limited usefulness for monitoring disease progression.

Revisting Cerebrospinal Fluid (CSF) Examination

Routine cerebrospinal fluid (CSF) examination bears re-visiting as the body of knowledge has expanded and numerous new analytes touted as potential markers of CNS (central nervous system) diseases have emerged. Currently, visual assessment of CSF, microscopic examination for pathologic cells, and biochemical analysis for protein and glucose form the basis for routine CSF analysis. Further investigations that may be warranted include microbiology work-ups for CNS infections and immuno-detection for oligoclonal bands for multiple sclerosis. European guidelines for CSF analyses are available. CSF testing for other neurologic disorders (e.g. Parkinson's disease, Alzheimer's disease, and amyotrophic lateral sclerosis) while promising are not ready for prime time.

TD-11 workshop report: characterization of monoclonal antibodies to S100 proteins

Fourteen monoclonal antibodies with specificity against native or recombinant antigens within the S100 family were investigated with regard to immunoreactivity. The specificities of the antibodies were studied using ELISA tests, Western blotting epitope mapping using competitive assays, and QCM technology. The mimotopes of antibodies against S100A4 were determined by random peptide phage display libraries. Antibody specificity was also tested by IHC and pair combinations evaluated for construction of immunoradiometric assays for S100B. Out of the 14 antibodies included in this report eight demonstrated specificity to S100B, namely MAbs 4E3, 4D2, S23, S53, 6G1, S21, S36, and 8B10. This reactivity could be classified into four different epitope groups using competing studies. Several of these MAbs did display minor reactivity to other S100 proteins when they were presented in denatured form. Only one of the antibodies, MAb 3B10, displayed preferential reactivity to S100A1; however, it also showed partial cross-reactivity with S100A10 and S100A13. Three antibodies, MAbs 20.1, 22.3, and S195, were specific for recombinant S100A4 in solution. Western blot revealed that MAb 20.1 and 22.3 recognized linear epitopes of S100A4, while MAb S195 reacted with a conformational dependent epitope. Surprisingly, MAb 14B3 did not demonstrate any reactivity to the panel of antigens used in this study.

S-100B and neuron-specific enolase as predictors of neurological outcome in patients after cardiac arrest and return of spontaneous circulation: a systematic review

INTRODUCTION

Neurological prognostic factors after cardiopulmonary resuscitation (CPR) in patients with cardiac arrest (CA) as early and accurately as possible are urgently needed to determine therapeutic strategies after successful CPR. In particular, serum levels of protein neuron-specific enolase (NSE) and S-100B are considered promising candidates for neurological predictors, and many investigations on the clinical usefulness of these markers have been published. However, the design adopted varied from study to study, making a systematic literature review extremely difficult. The present review focuses on the following three respects for the study design: definitions of outcome, value of specificity and time points of blood sampling.

METHODS

A Medline search of literature published before August 2008 was performed using the following search terms: "NSE vs CA or CPR", "S100 vs CA or CPR". Publications examining the clinical usefulness of NSE or S-100B as a prognostic predictor in two outcome groups were reviewed. All publications met with inclusion criteria were classified into three groups with respect to the definitions of outcome; "dead or alive", "regained consciousness or remained comatose", and "return to independent daily life or not". The significance of differences between two outcome groups, cutoff values and predictive accuracy on each time points of blood sampling were investigated.

RESULTS

A total of 54 papers were retrieved by the initial text search, and 24 were finally selected. In the three classified groups, most of the studies showed the significance of differences and concluded these biomarkers were useful for neurological predictor. However, in view of blood sampling points, the significance was not always detected. Nevertheless, only five studies involved uniform application of a blood sampling schedule with sampling intervals specified based on a set starting point. Specificity was not always set to 100%, therefore it is difficult to indiscriminately assess the cut-off values and its predictive accuracy of these biomarkers in this meta analysis.

CONCLUSIONS

In such circumstances, the findings of the present study should aid future investigators in examining the clinical usefulness of these markers and determination of cut-off values.

Serum S100B levels after meningioma surgery: A comparison of two laboratory assays

Background

S100B protein is a potential biomarker of central nervous system insult. This study quantitatively compared two methods for assessing serum concentration of S100B.

Methods

A prospective, observational study performed in a single tertiary medical center. Included were fifty two consecutive adult patients undergoing surgery for meningioma that provided blood samples for determination of S100B concentrations. Eighty samples (40 pre-operative and 40 postoperative) were randomly selected for batch testing. Each sample was divided into two aliquots. These were analyzed by ELISA (Sangtec) and a commercial kit (Roche Elecsys^®) for S100B concentrations. Statistical analysis included regression modelling and Bland-Altman analysis.

Results

A parsimonious linear model best described the prediction of commercial kit values by those determined by ELISA (y = 0.045 + 0.277*x, x = ELISA value, R² = 0.732). ELISA measurements tended to be higher than commercial kit measurements. This discrepancy increased linearly with increasing S100B concentrations. At concentrations above 0.7 μg/L the paired measurements were consistently outside the limits of agreement in the Bland-Altman display. Similar to other studies that used alternative measurement methods, sex and age related differences in serum S100B levels were not detected using the Elecsys^® (p = 0.643 and 0.728 respectively).

Conclusion

Although a generally linear relationship exists between serum S100B concentrations measured by ELISA and a commercially available kit, ELISA values tended to be higher than commercial kit measurements particularly at concentrations over 0.7 μg/L, which are suggestive of brain injury. International standardization of commercial kits is required before the predictive validity of S100B for brain damage can be effectively assessed in clinical practice.

Biological and methodological features of the measurement of S100B, a putative marker of brain injury

The S100B astroglial protein is widely used as a parameter of glial activation and/or death in several conditions of brain injury. Cerebrospinal fluid and serum S100B variations have been proposed to evaluate clinical outcomes in these situations. Here, we briefly broach some aspects, commonly not sufficiently valorized, concerning the biology and measurements of this protein. S100B has molecular targets and activities in and outside of astrocytes, and variations of intra and extracellular content are not necessarily coupled. We discuss the extracellular origin of this protein in brain tissue, as well as extracerebral sources of this protein in serum, comparing it with other available protein markers of brain damage. The superestimation of the heterodimer S100A1-B in the current clinical literature is also analyzed. We affirm that poor dualistic views that consider S100B elevation as "bad" or "good" simplify clinical practice and delay our comprehension of the role of this protein, both in physiological conditions and in brain disorders.

Reliability of S100B in predicting severity of central nervous system injury

S100B is a protein biomarker that reflects CNS injury. It can be measured in the CSF or serum with readily available immunoassay kits. The excellent sensitivity of S100B has enabled it to confirm the existence of subtle brain injury in patients with mild head trauma, strokes, and after successful resuscitation from cardiopulmonary arrest. The extent of S100B elevation has been found to be useful in predicting clinical outcome after brain injury. Elevations of S100B above certain threshold levels might be able to reliably predict brain death or mortality. A normal S100B level reliably predicts the absence of significant CNS injury. The specificity of S100B levels as a reflection of CNS injury is compromised by the findings that extra-cranial injuries can lead to elevations in the absence of brain injury. This potential problem can most likely be avoided by measuring serial S100B levels along with other biomarkers and carefully noting peripheral injuries. Serum markers GFAP and NSE are both more specific for CNS injury and have little to no extra-cranial sources. Sustained elevations of S100B over 24 h along with elevations of GFAP and NSE can more reliably predict the extent of brain injury and clinical outcomes. In the future, S100B measurements might reliably predict secondary brain injury and enable physicians to initiate therapeutic interventions in a timelier manner. S100B levels have been shown to rise hours to days before changes in ICP, neurological examinations, and neuroimaging tests. S100B levels may also be used to monitor the efficacy of treatments.

A review of the S100 proteins in cancer

AIM

In the quest to reduce mortality and morbidity from cancer, there is continued effort to identify novel biomarkers to aid in the early detection and the accurate prediction of tumour behaviour. One group of proteins that is emerging as a potentially important group of markers in multiple tumour types is the S100 family. This review summarises the biological and clinical relevance of these proteins in relation to different tumour types.

METHODS

A literature search was performed using the PubMed database and the reference lists of relevant articles. Single case studies were excluded and only reports with a clinical relevance from 1961 to 2007 were included.

RESULTS

The search yielded over 1000 published articles and reports. Important reports and studies were reviewed, screened and tracked for further relevant publications. Only the most relevant publications are discussed with relation to individual members of the S100 family.

CONCLUSION

There is increasing evidence that altered expression of S100 family members is seen in many cancers including breast, lung, bladder, kidney, thyroid, gastric, prostate and oral cancers. S100 proteins are commonly up-regulated in tumours and this is often associated with tumour progression. In contrast S100A2, S100A11 and S100A9 have been documented as tumour suppressors in some cancers but as tumour promoters in others. This demonstrates the complexity of the family and variability of their functions. Although the precise roles of these proteins in cancer is still to be discovered many of the family are associated with promoting metastases through interactions with matrix metalloproteinases or by acting as chemoattractants. There is also evidence that some members can regulate transcription factors such as p53. S100B already has a role in a clinical setting in the diagnosis and therapeutic monitoring of malignant melanoma. As our understanding of this family develops it is likely that many more members will aid the diagnosis, monitoring and potential treatment of cancers in the future.

Distribution of HLA-DR-positive microglia in schizophrenia reflects impaired cerebral lateralization

Immunological alterations have been demonstrated in peripheral blood and cerebrospinal fluid of patients with schizophrenia, while previous postmortem studies have provided an inconsistent picture as to the role of microglia in the context of schizophrenia. Microglial activation is a sensitive indicator of changes in the CNS microenvironment, such as inflammatory and neurodegenerative processes. The aim of the present postmortem study was to examine HLA class II (HLA-DR) expression on microglia in brain regions which are particularly relevant for schizophrenia, with regard to hemispheric lateralization. Dorsolateral prefrontal cortex (DLPFC), anterior cingulate cortex (ACC), hippocampus and mediodorsal thalamus (MD) were studied in 16 cases with schizophrenia and 16 control subjects. Immunostaining was found in all brain regions and was not restricted to macrophage-like ameboid cells, but also appeared in ramified cells. Region-specific HLA-DR-positive cell density was not significantly different between cases with schizophrenia and controls. However, ameboid microglial cells were lateralized towards the right hemisphere in healthy subjects but not in the schizophrenia group (P=0.01). Postmortem interval correlated with ramified cell numbers in ACC/DLPFC (P=0.01/0.04) and ameboid cell density in hippocampus (P=0.03). Age, gender, duration of disease, medication dosage, storage delay and whole brain volume had no effect. Single case analysis revealed highly elevated microglial cell numbers in ACC and MD of two schizophrenic patients who had committed suicide during acute psychosis. In conclusion, the present data suggest the absence of microgliosis but decreased cerebral lateralization of ameboid microglia in schizophrenia.

Acute and chronic electroconvulsive shock in rats: Effects on peripheral markers of neuronal injury and glial activity

Electroconvulsive therapy is considered one of the most effective treatments of major depression, but controversy still exists on whether it may be brain damaging. The aim of this work was to evaluate the cerebrospinal fluid (CSF) levels of neuron specific enolase (NSE), protein S100B and lactate of rats submitted to acute and chronic models of ECS. Rats were submitted to either one shock (acute) or a series of eight shocks, applied one at every 48 h (chronic). CSF samples were collected at 0, 3, 6, 12, 24, 48 and 72 h after the shock in the acute model and at these same time intervals after the last shock in the chronic model. Both models did not produce significant alterations in the levels of NSE. S100B levels were significantly increased at 6 h in the chronic model (p<0.0001). There was a significant increase in the levels of lactate at 0 h in both models (p<0.001). These results support the proposition that ECS does not produce neural damage, and suggest that the alterations in the levels of S100B and lactate may reflect an astrocytic activity of a protective nature.

Biochemical brain markers and purinergic parameters in rat CSF after seizure induced by pentylenetetrazol

Cellular and molecular mechanisms involved in the generation of seizures and the magnitude of neural cells injury are not fully understood. We evaluated astrocyte and/or neuronal injury in rats in the pentylenetetrazol model of acute seizures by measuring S100B and NSE levels in cerebrospinal fluid. Additionally, we determined ADP and GDP hydrolysis by soluble nucleoside triphosphate diphosphohydrolase in the cerebrospinal fluid, and the concentration of nucleosides adenosine, inosine and guanosine as putative markers of brain injury. After pentylenetetrazol-induced seizures: (i) S100B values increased from 10 to 30 min, returning to control levels at 24 h; NSE levels presented a biphasic increase: an increase at 10 to 30 min returning to control levels, and again at 240 min followed by a decline at 24 h; (ii) nucleotidase activities increased from 10 min, returning to control levels at 240 min; (iii) guanosine and inosine levels increased exclusively after 30 min. In summary, this study showed biochemical changes in the cerebrospinal fluid occurring after seizures induced by pentylenetetrazol. Such events may have a modulating effect upon seizure expression, particularly nucleoside triphosphate diphosphohydrolase activities and nucleoside concentrations, but are nevertheless followed by neural death as evidenced by the increase in NSE and S100B levels.

The ischemic rat heart releases S100B

S100B is an astrocytic protein assessed in cerebrospinal fluid and serum as a biochemical marker of cerebral injuries. However, increasing evidences suggest the influence of extra cerebral sources on its serum levels. Since it was reported that the injured myocardium expresses S100B, we investigated whether the isolated heart releases this protein. The rat hearts were excised and perfused by the Langendorff technique of isolated heart perfusion. After stabilization, 10 hearts (ischemic group) were submitted to 20 minutes of ischemia and 30 minutes of reperfusion, and 5 hearts (control group) were submitted to 50 minutes of perfusion. The perfusion fluid was collected at pre-ischemia, and 0, 5, 10, 15 and 30 min after ischemia (or equivalent in controls) for S100B and cardiac troponin T (a heart injury marker) assays. In the ischemic group, S100B and troponin T levels increased significantly at time 0 min: S100B values [mug/L, median (IQ25/IQ75)] increased from < or = 0.02 (< or = 0.02/0.03) to 0.38 (0.22/0.84), while troponin T values [mug/L, median (IQ25/IQ75)] increased from 0.31 (0.15/0.45) to 2.84 (2.00/3.63). Our results point to the ischemic heart as an extra cerebral source of S100B.

Expression of S100 proteins in normal human tissues and common cancers using tissue microarrays: S100A6, S100A8, S100A9 and S100A11 are all overexpressed in common cancers

AIMS

To survey the expression of members of the S100 family of calcium-binding proteins in normal human tissues and common cancers using tissue microarrays. S100A6, S100A8, S100A9 and S100A11 have all been suggested to have potential roles in carcinogenesis and tumour progression but their expression has not been described in a wide range of human tissues and tumours.

METHODS AND RESULTS

A custom-made tissue array, containing 291 tissue cores representing 28 tissue types and 21 tumour types, was used to produce sections that were immunostained for S100A2, S100A6, S100A8, S100A9, S100A11, calbindin 1, calbindin 2, S100B and parvalbumin. S100A6, S100A8 and S100A9 were expressed in 32%, 12% and 28% of breast cancers, respectively. There was a translocation of S100A11 expression from exclusively nuclear in normal tissues to cytoplasmic and nuclear in all common cancers.

CONCLUSIONS

S100A6, S100A8, S100A9 and S100A11 are all expressed in common cancers, especially breast cancer. In addition, S100A11 undergoes a nucleocytoplasmic translocation which may have a direct influence on the proliferation of the cancer cells.

S100 proteins as cancer biomarkers with focus on S100B in malignant melanoma

Although histochemical staining of the S100 protein family has been used for many years in the diagnosis of malignant melanoma, recent studies suggest one of the proteins comprising the S100 family, S100B, has particular utility in many aspects of the clinical management of malignant melanoma. This protein has been shown to be of use in staging malignant melanoma, in establishing prognosis, in evaluating treatment success and in predicting relapse. S100B is an independent prognostic factor and pretreatment circulating S100B concentrations predict duration of survival in melanoma patients. Survival is significantly longer in melanoma patients with normal S100B levels compared to those with elevated levels. Circulating S100B levels very sensitively detect metastatic growth of malignant melanoma, particularly in stage IV disease where S100B is certainly superior to other laboratory parameters. S100B concentrations reflect tumor mass. Serum S100B levels predict efficacy of treatment. Decreasing S100B concentrations reflect response to therapy while increasing S100B concentrations indicate tumor progression. Circulating S100B has a role to play in the decision to switch treatment regimens.