Reliable detection of genetic alterations in cyst fluid DNA for the diagnosis of brain tumors.

PURPOSE: Liquid biopsy of cyst fluid in brain tumors has not been extensively studied to date. The present study was performed to see whether diagnostic genetic alterations found in brain tumor tissue DNA could also be detected in cell-free DNA (cfDNA) of cyst fluid in cystic brain tumors. METHODS: Cyst fluid was obtained from 22 patients undergoing surgery for a cystic brain tumor with confirmed genetic alterations in tumor DNA. Pathological diagnoses based on WHO 2021 classification and diagnostic alterations in the tumor DNA, such as IDH1 R132H and TERT promoter mutation for oligodendrogliomas, were detected by Sanger sequencing. The same alterations were analyzed by both droplet digital PCR (ddPCR) and Sanger sequencing in cyst fluid cfDNA. Additionally, multiplex ligation-dependent probe amplification (MLPA) assays were performed to assess 1p/19q status, presence of CDKN2A loss, PTEN loss and EGFR amplification, to assess whether differentiating between astrocytomas and oligodendrogliomas and grading is possible from cyst fluid cfDNA. RESULTS: Twenty-five genetic alterations were found in 22 tumor samples. All (100%) alterations were detected in cyst fluid cfDNA by ddPCR. Twenty of the 25 (80%) alterations were also detected by Sanger sequencing of cyst fluid cfDNA. Variant allele frequency (VAF) in cyst fluid cfDNA was comparable to that of tumor DNA (R = 0.62, Pearson's correlation). MLPA was feasible in 11 out of 17 (65%) diffuse gliomas, with close correlation of results between tumor DNA and cyst fluid cfDNA. CONCLUSION: Cell-free DNA obtained from cyst fluid in cystic brain tumors is a reliable alternative to tumor DNA when diagnosing brain tumors.

Clinical, imaging, and molecular features of radiation-induced glioblastomas developing more than 20 years after radiation therapy for intracranial germinomatous germ cell tumor: illustrative cases.

BACKGROUND: Germinomatous germ cell tumor is highly sensitive to chemoradiotherapy; patients are expected to survive for decades. Many radiation-induced malignant gliomas (RIMGs) occur >10 years after radiotherapy. Standard therapy for RIMGs has not been established because of the lesion's rarity, the patient's shorter survival period, and the risk of radiation necrosis by repeat radiation. OBSERVATIONS: Two patients, a 32-year-old man and a 50-year-old man, developed glioblastomas more than 20 years after radiation monotherapy for germinoma with or without mature teratoma. The first patient showed a tumor in the left frontotemporal region with disseminated lesions and died 2 months after partial resection of the tumor without responding to the chemotherapy with temozolomide and bevacizumab. Methylation classifier analysis classified the pathology as closest to diffuse pediatric-type high-grade glioma, Rtk1 subtype. The second patient showed a tumor mass in the brainstem and left cerebellar peduncle, which worsened progressively during chemotherapy with temozolomide and bevacizumab. The tumor transiently responded to stereotactic radiotherapy with the CyberKnife. However, the patient died of RIMG recurrence-related aspiration pneumonia 11 months after the biopsy. Methylation classifier analysis classified the pathology as closest to infratentorial pilocytic astrocytoma. LESSONS: Chemoradiotherapy may improve the survival of patients with RIMGs. Furthermore, molecular features may influence the clinical, locoregional, and pathological features of RIMG.

Elevated ratio of C-type lectin-like receptor 2 level and platelet count (C2PAC) aids in the diagnosis of post-operative venous thromboembolism in IDH-wildtype gliomas.

INTRODUCTION: Podoplanin (PDPN) is known to induce platelet aggregation via interacting with the C-type lectin-like receptor-2 on platelets and is involved in postoperative venous thromboembolism (VTE) formation. In this study, we investigate the correlation between soluble C-type lectin-like receptor (sCLEC-2) levels and PDPN expression in patients with high grade gliomas and the relationship between sCLEC-2 levels and the occurrence of VTE. MATERIALS AND METHODS: Forty-four patients harboring high grade gliomas, treated surgically at the Department of Neurosurgery, Niigata University from April 2018 to August 2020, were included. Patients with high grade gliomas were divided into isocitrate dehydrogenase (IDH)- wildtype and mutant groups, and the presence or absence of VTE and the intensity of PDPN by immunohistochemistry were confirmed. Platelet counts, as well as plasma sCLEC-2 and PDPN were measured in these patients. Furthermore, the levels of sCLEC-2 concentration were divided by the platelet count (C2PAC index) for comparison. RESULTS: IDH-wildtype glioma patients highly expressed PDPN (P < 0.001) compared to IDH-mutant glioma patients. In total, 9 (20.5 %) patients were diagnosed with VTE during the follow-up period, of which 8 patients harbored IDH-wildtype gliomas, and one patient an IDH-mutant glioma. Mean sCLEC-2 levels and C2PAC index in patients with IDH-wildtype gliomas were significantly higher than that of low or no PDPN expression group, which included patients with IDH-mutant gliomas (P = 0.0004, P = 0.0002). In patients with IDH-wildtype gliomas, the C2PAC index in patients with VTE was significantly higher than in patients without VTE (P = 0.0492). The optimal cutoff point of C2PAC for predicting VTE in IDH-wildtype glioma patients was 3.7 with a sensitivity of 87.5 % and specificity of 51.9 %. CONCLUSION: Platelet activation is strongly involved in the development of VTE in patients with IDH-wildtype high grade gliomas, and C2PAC index is a potential marker to detect VTE formation after surgery.

Successful Treatment of Acute Uric Acid Nephropathy with Rasburicase in a Primary Central Nervous System Lymphoma Patient Showing a Dramatic Response to Methotrexate-Case Report.

BACKGROUND: Primary central nervous system lymphomas (PCNSLs) are sensitive to chemotherapy. The standard treatment is high-dose methotrexate (MTX)-based chemotherapy. There are no reports of successful treatment of acute uric acid nephropathy with rasburicase after MTX administration in PCNSLs. CASE PRESENTATION: A 54-year-old man with a history of gout presented with a change in character and cognitive dysfunction. MRI showed a large enhancing mass spanning the bilateral frontal lobes and the right temporal lobe. After endoscopic biopsy, an MTX, procarbazine, and vincristine (MPV) regimen was initiated for the treatment of the PCNSL. After the initiation of chemotherapy, the patient experienced a gout attack, and blood examination revealed acute renal failure (ARF) and hyperuricemia. The considered causes of ARF included MTX toxicity and acute uric acid nephropathy. As the dramatic effect of MTX was observed, treatment was continued despite ARF, most probably due to acute hyperuricemia due to tumor lysis, which was treated in parallel. After an improvement in renal function, MTX was resumed, and rasburicase was initiated to control hyperuricemia. A complete response was obtained after induction chemotherapy. Hyperuricemia was controlled with rasburicase, and renal function was preserved. CONCLUSIONS: Acute uric acid nephropathy should be considered when ARF occurs after the initiation of MTX in PCNSLs, especially in newly diagnosed PCNSL patients with large tumors or hyperuricemia.

Novel Repositioning Therapy for Drug-Resistant Glioblastoma: In Vivo Validation Study of Clindamycin Treatment Targeting the mTOR Pathway and Combination Therapy with Temozolomide.

Multimodal therapy including surgery, radiation treatment, and temozolomide (TMZ) is performed on glioblastoma (GBM). However, the prognosis is still poor and there is an urgent need to develop effective treatments to improve survival. Molecular biological analysis was conducted to examine the signal activation patterns in GBM specimens and remains an open problem. Advanced macrolides, such as azithromycin, reduce the phosphorylation of p70 ribosomal protein S6 kinase (p70S6K), a downstream mammalian target of rapamycin (mTOR) effector, and suppress the proliferation of T-cells. We focused on its unique profile and screened for the antitumor activity of approved macrolide antibiotics. Clindamycin (CLD) reduced the viability of GBM cells in vitro. We assessed the effects of the candidate macrolide on the mTOR pathway through Western blotting. CLD attenuated p70S6K phosphorylation in a dose-dependent manner. These effects on GBM cells were enhanced by co-treatment with TMZ. Furthermore, CLD inhibited the expression of the O6-methylguanine-DNA methyltransferase (MGMT) protein in cultured cells. In the mouse xenograft model, CLD and TMZ co-administration significantly suppressed the tumor growth and markedly decreased the number of Ki-67 (clone MIB-1)-positive cells within the tumor. These results suggest that CLD suppressed GBM cell growth by inhibiting mTOR signaling. Moreover, CLD and TMZ showed promising synergistic antitumor activity.

Dramatic response of BRAF V600E-mutant epithelioid glioblastoma to combination therapy with BRAF and MEK inhibitor: establishment and xenograft of a cell line to predict clinical efficacy.

Epithelioid glioblastoma is a rare aggressive variant of glioblastoma (GBM) characterized by a dismal prognosis of about 6 months and frequent leptomeningeal dissemination. A recent study has revealed that 50% of epithelioid GBMs harbor three genetic alterations - BRAF V600E mutation, TERT promoter mutations, and homozygous deletions of CDKN2A/2B. Emerging evidence support the effectiveness of targeted therapies for brain tumors with BRAF V600E mutation. Here we describe a dramatic radiographical response to combined therapy with BRAF and MEK inhibitors in a patient with epithelioid GBM harboring BRAF V600E mutation, characterized by thick spinal dissemination. From relapsed tumor procured at autopsy, we established a cell line retaining the BRAF V600E mutation, TERT promoter mutation and CDKN2A/2B loss. Intracranial implantation of these cells into mice resulted in tumors closely resembling the original, characterized by epithelioid tumor cells and dissemination, and invasion into the perivascular spaces. We then confirmed the efficacy of treatment with BRAF and MEK inhibitor both in vitro and in vivo. Epithelioid GBM with BRAF V600E mutation can be considered a good treatment indication for precision medicine, and this patient-derived cell line should be useful for prediction of the tumor response and clarification of its biological characteristics.

EGFRvIII Is Expressed in Cellular Areas of Tumor in a Subset of Glioblastoma.

Epidermal growth factor receptor variant III (EGFRvIII) is a tumor-specific cell surface antigen often expressed in glioblastoma and has drawn much attention as a possible therapeutic target. We performed immunohistochemistry on histology sections of surgical specimens taken from 67 cases with glioblastoma, isocitrate dehydrogenase-wild type, and evaluated the morphological characteristics and distribution of the EGFRvIII-positive tumor cells. We then evaluated the localization of EGFRvIII-expression within the tumor and peritumoral areas. EGFRvIII immunopositivity was detected in 15 specimens taken from 13 patients, including two recurrent specimens taken from the same patient at relapse. Immunofluorescence staining demonstrated that EGFRvIII-positive cells were present in cells positive for glial fibrillary acidic protein (GFAP), and some showed astrocytic differentiation with multiple fine processes and others did not shown. The EGFRvIII-positive cells were located in cellular areas of the tumor, but not in the invading zone. In the two recurrent cases, EGFRvIII-positive cells were markedly decreased in one case and retained in the other. With regard to overall survival, univariate analysis indicated that EGFRvIII-expression in patients with glioblastoma was not significantly associated with a favorable outcome. Double-labeling immunofluorescence staining of EGFRvIII and GFAP showed that processes of large, well differentiated, GFAP-positive glia extend to and surround less differentiated, EGFRvIII-positive glial cells in cellular areas of tumor. However, in the tumor periphery, EGFRvIII-positive tumor cells were not observed. This finding suggests that EGFRvIII is involved in tumor proliferation, but that invading glioma cells lose their EGFRvIII expression.

Neurobehavioral deficits of epidermal growth factor-overexpressing transgenic mice: impact on dopamine metabolism.

Epidermal growth factor (EGF) and its family member neuregulin-1 are implicated in the etiology of schizophrenia. Our recent pharmacological studies indicate that EGF injections to neonatal and adult rats both induce neurobehavioral deficits relevant to schizophrenia. We, however, did not evaluate the genetic impact of EGF transgene on neurobehavioral traits. Here we analyzed transgenic mice carrying the transgene of mouse EGF cDNA. As compared to control littermates, heterozygous EGF transgenic mice had an increase in EGF mRNA levels and showed significant decreases in prepulse inhibition and context-dependent fear learning, but there were no changes in locomotor behaviors and sound startle responses. In addition, these transgenic mice exhibited higher behavioral sensitivity to the repeated cocaine injections. There were neurochemical alterations in metabolic enzymes of dopamine (i.e., tyrosine hydroxylase, dopa decarboxylase, catechol-O-methyl transferase) and monoamine contents in various brain regions of the EGF transgenic mice, but there were no apparent neuropathological signs in the brain. The present findings rule out the indirect influence of anti-EGF antibody production on the reported behavioral deficits of EGF-injected mice. These results support the argument that aberrant hyper-signals of EGF have significant impact on mouse behavioral traits and dopamine metabolism.

Antipsychotic potential of quinazoline ErbB1 inhibitors in a schizophrenia model established with neonatal hippocampal lesioning.

Hyper-signaling of the epidermal growth factor receptor family (ErbB) is implicated in the pathophysiology of schizophrenia. Various quinazoline inhibitors targeting ErbB1 or ErbB2 - 4 have been developed as anti-cancer agents and might be useful for antipsychotic treatment. In the present study, we used an animal model of schizophrenia established by neonatal hippocampal lesioning and evaluated the neurobehavioral consequences of ErbB1-inhibitor treatment. Subchronic administration of the ErbB1 inhibitor ZD1839 to the cerebroventricle of rats receiving neonatal hippocampal lesioning ameliorated deficits in prepulse inhibition as well as those in the latent inhibition of tone-dependent fear learning. There were no apparent adverse effects on basal learning scores or locomotor activity, however. The administration of other ErbB1 inhibitors, PD153035 and OSI-774, similarly attenuated the prepulse inhibition impairment of this animal model. In parallel, there were decreases in ErbB1 phosphorylation in animals treated with ErbB1 inhibitors. These results indicate an antipsychotic potential of quinazoline ErbB1 inhibitors. ErbB receptor tyrosine kinases may be novel therapeutic targets for schizophrenia or its related psychotic symptoms.

A cyclooxygenase-2 inhibitor ameliorates behavioral impairments induced by striatal administration of epidermal growth factor.

Consistent with the hypothesis that neuroinflammatory processes contribute to the neuropathology of schizophrenia, the protein levels of epidermal growth factor (EGF) and its receptor ErbB1 are abnormal in patients with schizophrenia. To evaluate neuropathological significance of this abnormality, we established an animal model for behavioral deficits by administering EGF into the striatum and evaluated the effects of cyclooxygenase-2 (Cox-2) inhibitor celecoxib. Intracranial infusion of EGF into the striatum of adult male rats activated ErbB1 and induced neurobehavioral impairments observed in several schizophrenia models. Unilateral EGF infusion to the striatum lowered prepulse inhibition (PPI) in a dose-dependent manner and impaired latent learning of active shock avoidance without affecting basal learning ability. Bilateral EGF infusion similarly affected PPI. In contrast, EGF infusion to the nucleus accumbens did not induce a behavioral deficit. Intrastriatal EGF infusion also increased Cox-2 expression, elevated tyrosine hydroxylase activity, and upregulated the levels of dopamine and its metabolites. Subchronic administration of celecoxib (10 mg/kg, p.o.) ameliorated the abnormalities in PPI and latent learning as well as normalized dopamine metabolism. We conclude that this EGF-triggered neuroinflammatory process is mediated in part by Cox-2 activity and perturbs dopamine metabolism to generate neurobehavioral abnormalities.