Ferritin in glioblastoma.

Elevated levels of serum ferritin (SF) are observed in several types of cancer; however, little is known on the association between ferritin and glioma, the most frequent type of human primary brain tumour. Here we report that GBM patients show significantly increased pre-surgical SF levels (i.e. ferritinaemia) within the SF reference range and a marked ferritin immunoreactivity of resected tumour tissue. Our findings account for an indirect association between ferritin synthesis in glioma-tissue and altered SF levels, which limits the clinical value of SF as a tumour marker in glioma. Importantly, we show for the first time that GBM-derived glioma cells release ferritin in vitro, which exerts an apoptosis-stimulating activity. Albeit the pathophysiologic context of apoptosis induction by a tumour-derived ferritin remains to be defined, our findings account for a distinct growth-regulatory role of these ferritin species in tumour biology.

Proseek single-plex protein assay kit system to detect sAxl and Gas6 in serological material of brain tumor patients.

•The receptor tyrosine kinase (RTK) Axl and its ligand Gas6 are critically involved in the pathogenesis of high-grade glioma (HGG). Both proteins were found to be overexpressed e.g. in tumor cells, mediating cell proliferation and migration as well as tumor angiogenesis and neuroinflammation. The extracellular domain of Axl (sAxl) and Gas6 were found in the peri-tumoral edema and blood of animals as well as in human glioma tissue. Therefore, we monitored the level of sAxl and Gas6 in human blood samples. To increase the sensitivity of protein detection beyond commonly used standard methods we preliminary tested the innovative Proseek Single-Plex Protein Assay Kit System from Olink Bioscience together with new antibodies against the soluble RTK sAxl and its ligand Gas6. We conclude that the Proseek method is a highly sensitive and fast procedure that can be used as a possible powerful tool compared to routinely used ELISA-methods.

Epileptic Activity Increases Cerebral Amino Acid Transport Assessed by 18F-Fluoroethyl-l-Tyrosine Amino Acid PET: A Potential Brain Tumor Mimic.

O-(2-18F-fluoroethyl)-l-tyrosine (18F-FET) PET is a well-established method increasingly used for diagnosis, treatment planning, and monitoring in gliomas. Epileptic activity, frequently occurring in glioma patients, can influence MRI findings. Whether seizures also affect 18F-FET PET imaging is currently unknown. The aim of this retrospective analysis was to investigate the brain amino acid metabolism during epileptic seizures by 18F-FET PET and to elucidate the pathophysiologic background. METHODS: Ten patients with 11 episodes of serial seizures or status epilepticus, who underwent MRI and 18F-FET PET, were studied. The main diagnosis was glioma World Health Organization grade II-IV (n = 8); 2 patients suffered from nonneoplastic diseases. Immunohistochemical assessment of LAT1/LAT2/CD98 amino acid transporters was performed in seizure-affected cortex (n = 2) and compared with glioma tissues (n = 3). RESULTS: All patients exhibited increased seizure-associated strict gyral 18F-FET uptake, which was reversible in follow-up studies or negative shortly before and without any histologic or clinical signs of tumor recurrence. 18F-FET uptake corresponded to structural MRI changes, compatible with cortical vasogenic and cytotoxic edema, partial contrast enhancement, and hyperperfusion. Patients with prolonged postictal symptoms lasting up to 8 wk displayed intensive and widespread (≥ 1 lobe) cortical 18F-FET uptake. LAT1/LAT2/CD98 was strongly expressed in neurons and endothelium of seizure-affected brains and less in reactive astrocytosis. CONCLUSION: Seizure activity, in particular status epilepticus, increases cerebral amino acid transport with a strict gyral 18F-FET uptake pattern. Such periictal pseudoprogression represents a potential pitfall of 18F-FET PET and may mimic brain tumor. Our data also indicate a seizure-induced upregulation of neuronal, endothelial, and less astroglial LAT1/LAT2/CD98 amino acid transporter expression.