Search

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.

Black hairy tongue (BHT) developed in five patients (2.6%) among 192 patients undergoing chemotherapy for malignant brain tumors. Three patients with a history of diabetes mellitus developed BHT within 10 days after the initiation of chemotherapy. The other two patients suffered more than 100 days after induction and lymphopenia of grade 3 or worse developed for more than 20 days, which was not observed in the three patients with diabetes. We found that BHT could develop after chemotherapy for malignant brain tumors. Patients with diabetes mellitus presented early after chemotherapy, while patients with longstanding severe lymphopenia presented in late phase.

The prognostic impact of TERT mutations has been controversial in IDH-wild tumors, particularly in glioblastomas (GBM). The controversy may be attributable to presence of potential confounding factors such as MGMT methylation status or patients’ treatment. This study aimed to evaluate the impact of TERT status on patient outcome in association with various factors in a large series of adult diffuse gliomas. We analyzed a total of 951 adult diffuse gliomas from two cohorts (Cohort 1, n = 758; Cohort 2, n = 193) for IDH1/2, 1p/19q, and TERT promoter status. The combined IDH/TERT classification divided Cohort 1 into four molecular groups with distinct outcomes. The overall survival (OS) was the shortest in IDH wild-type/TERT mutated groups, which mostly consisted of GBMs (P

Extracellular free amino acids contribute to the interaction between a tumor and its microenvironment through effects on cellular metabolism and malignant behavior. System xc(–) is composed of xCT and CD98hc subunits and functions as a plasma membrane antiporter for the uptake of extracellular cystine in exchange for intracellular glutamate. Here, we show that the EGFR interacts with xCT and thereby promotes its cell surface expression and function in human glioma cells. EGFR-expressing glioma cells manifested both enhanced antioxidant capacity as a result of increased cystine uptake, as well as increased glutamate, which promotes matrix invasion. Imaging mass spectrometry also revealed that brain tumors formed in mice by human glioma cells stably overexpressing EGFR contained higher levels of reduced glutathione compared with those formed by parental cells. Targeted inhibition of xCT suppressed the EGFR-dependent enhancement of antioxidant capacity in glioma cells, as well as tumor growth and invasiveness. Our findings establish a new functional role for EGFR in promoting the malignant potential of glioma cells through interaction with xCT at the cell surface. Cancer Res; 76(10); 2954–63. ©2016 AACR.

Objective This single-arm, open-label, Phase II study evaluated the efficacy and safety of single-agent bevacizumab, a monoclonal antibody against vascular endothelial growth factor, in Japanese patients with recurrent malignant glioma. Methods Patients with histologically confirmed, measurable glioblastoma or World Health Organization Grade III glioma, previously treated with temozolomide plus radiotherapy, received 10 mg/kg bevacizumab intravenous infusion every 2 weeks. The primary endpoint was 6-month progression-free survival in the patients with recurrent glioblastoma. Results Of the 31 patients enrolled, 29 (93.5%) had glioblastoma and 2 (6.5%) had Grade III glioma. Eleven (35.5%) patients were receiving corticosteroids at baseline; 17 (54.8%) and 14 (45.2%) patients had experienced one or two relapses, respectively. The 6-month progression-free survival rate in the 29 patients with recurrent glioblastoma was 33.9% (90% confidence interval, 19.2-48.5) and the median progression-free survival was 3.3 months. The 1-year survival rate was 34.5% with a median overall survival of 10.5 months. There were eight responders (all partial responses) giving an objective response rate of 27.6%. The disease control rate was 79.3%. Eight of the 11 patients taking corticosteroids at baseline reduced their dose or discontinued corticosteroids during the study. Bevacizumab was well-tolerated and Grade ≥3 adverse events of special interest to bevacizumab were as follows: hypertension [3 (9.7%) patients], congestive heart failure [1 (3.2%) patient] and venous thromboembolism [1 (3.2%) patient]. One asymptomatic Grade 1 cerebral hemorrhage was observed, which resolved without treatment. Conclusion Single-agent bevacizumab provides clinical benefit for Japanese patients with recurrent glioblastoma.

Background An advanced glycation end product has been implicated in a wide range of pathologic conditions, including diabetes mellitus, chronic kidney diseases, cardiovascular diseases, and arteriosclerosis. Little is known about its relationship with cerebral ischemia. The authors investigated serum levels of pentosidine and outcomes of patients with acute ischemic stroke Methods Serum pentosidine levels were measured in 83 patients with acute ischemic stroke at initial hospitalization and other risk factors of stroke. Outcomes of patients at 30 days from hospitalization were assessed by using modified Rankin Scale (mRS) score. Univariate and multivariate logistic regression analyses were performed to analyze the relationship between pentosidine and patient outcomes. Results In the univariate logistic regression analyses, poor outcomes, defined as mRS scores of >2, at 30 days were significantly related to high serum pentosidine ( P = .001), type of stroke ( P = .045), old age ( P = .02), male sex ( P = .042), and the absence of dyslipidemia ( P = .02). Deterioration of mRS was significantly correlated with high serum pentosidine ( P = .003) and creatinine ( P = .02). Multivariate logistic regression analysis showed that a high level of serum pentosidine was the only independent risk factor for poor outcomes ( P = .004) and deterioration of mRS ( P = .01) at 30 days. Conclusions A high level of serum pentosidine indicates poor and worse outcomes 30 days after acute ischemic stroke. This new biomarker is useful for risk stratification of patients with acute ischemic stroke.

Backgrounds: Mutations of the isocitrate dehydrogenase 1 (IDH1) or 2 (IDH2) genes are present in most WHO grade II/III gliomas and secondary glioblastoma (GBM), thus being of essential importance in the diagnosis and decision for therapeutic options Mutant IDH (mut-IDH) 1 or 2 catalyzes production of 2-hydroxyglutarate (2-HG), which acts as an “oncometabolite” leading to gliomagenesis through activation of cardinal biological pathways. LCModel is a software which can detect and conduct quantitative analysis of metabolites including 2-HG using data from proton-magnetic resonance spectroscopy (H-MRS). Here we report our experience using this method focusing on its sensitivity, specificity, and accuracy in detection of 2-HG in a variety of intracerebral lesions mostly of gliomas. Methods: Patients with brain tumor that was examined with 3T MRS (single voxel, PRESS sequence) from December, 2014 to November, 2016 were eligible. The acquired MRS data were analyzed with LCModel, which then were compared with pathological diagnosis and gene mutation profiles of the lesions. There were 147 patients, 65 males and 82 females, and their mean age was 53 years (range, 6–91 years) Mutations of IDH1/2 genes were identified by Sanger sequencing. Accuracy of the metabolite concentration measurement was determined with standard deviation rate (%SD) provided by LCModel analysis and a threshold for exclusion was set at 50% or greater of %SD. Results: IDH mutation was found in 39 gliomas while IDH was wild-type (wt-IDH) in 29 gliomas. There were 22 other neoplastic lesions including meningiomas and primary nervous system lymphomas, and additional 57 without histopathological confirmation. Those with mut-IDH were significantly younger (p=0.002). IDH mutation was significantly associated with methylation in promoter region of O6-methylguanine-DNA methyltransferase (MGMT) gene (p=0.027). Among a total of 276 H-MRS analyses (132 mut-IDHs, 44 wt-IDHs, 29 other tumors and 71 unconfirmed lesions), 2-HG was detectable in 23 analyses where mean 2-HG concentration was 6.01 mmol/L (range 1.831–15.203). Among 23 2-HG detected lesions, 9 were found to be positive for IDH mutation, while 2-HG levels were 0 mmol/L in all 64 wt-IDH gliomas and other brain tumors, giving rise to sensitivity of 11%, specificity 86%, and accuracy of 66%. Of note, 2-HG detected lesions with IDH mutation contained significantly higher concentration of aspartic acid (Asp) than those without IDH mutation (1.49 vs. 0.56 mmol/L, p=0.046). Conclusions: 2-HG could be detected in human glioma lesions with mut-IDH using MRS-LCModel system, but the sensitivity was insufficient for reliable non-invasive diagnosis. Given that Asp is synthesized from oxaloacetate in the citric acid cycle, association of increased Asp level with 2-HG might provide a potential usefulness in enhancing accuracy of this method, although further exploration is warranted.

Recent collaborative efforts have subclassified malignant glioblastomas into 4 clinical relevant subtypes based on their signature genetic lesions. Platelet-derived growth factor receptor α (PDGFRA) overexpression is concomitant with a loss of cyclin-dependent kinase inhibitor 2A (CDKN2A) locus (encoding P16INK4A and P14ARF) in a large number of tumors within one subtype of glioblastomas. Here we report that activation of PDGFRα conferred tumorigenicity to Ink4a/Arf-deficient mouse astrocytes and human glioma cells in the brain. Restoration of p16INK4a but not p19ARF suppressed PDGFRα-promoted glioma formation. Mechanistically, abrogation of signaling modules in PDGFRα that lost capacity to bind to SHP-2 or PI3K significantly diminished PDGFRα-promoted tumorigenesis. Furthermore, inhibition of SHP-2 by shRNAs or pharmacological inhibitors disrupted the interaction of PI3K with PDGFRα, suppressed downstream AKT/mTOR activation, and impaired tumorigenesis of Ink4a/Arf-null cells, whereas expression of an activated PI3K mutant rescued the effect of SHP-2 inhibition on tumorigenicity. PDGFRα and PDGF-A are co-expressed in clinical glioblastoma specimens, and such co-expression is linked with activation of SHP-2/AKT/mTOR signaling. Together, our data suggest that in glioblastomas with Ink4a/Arf deficiency, overexpressed PDGFRα promotes tumorigenesis through the PI3K/AKT/mTOR-mediated pathway regulated by SHP-2 activity. These findings functionally validate the genomic analysis of glioblastomas and identify SHP-2 as a potential target for treatment of glioblastomas.

BACKGROUND: Standard of care for newly diagnosed glioblastoma (GBM) has been chemoradiotherapy with concomitant and adjuvant temozolomide (TMZ) (Stupp regimen). Optimal number of adjuvant TMZ cycles, however, has not been well established yet, although the pivotal trial used 6 cycles. In routine practice, up to 24 cycles have been frequently given, while many recent trials have adopted 12 cycles without solid evidence. Here we investigated outcome of and prognostic factors associated with discontinuation of adjuvant TMZ after 12 cycles without progression. METHODS: Ninety six patients treated with Stupp regimen since May 2007 to March 2017 in our institution were retrospectively analyzed. Overall survival (OS) and progression-free survival (PFS) were evaluated with Kaplan-Meier method and statistical significance was determined by logrank test. RESULTS: There were 20 patients (21%, med age 57 yo; med KPS 70; female 12) identified who completed 12 adjuvant TMZ cycles without progression. Nine patients discontinued adjuvant TMZ (Group A), while 11 continued beyond 12 cycles (Group B). Median PFS (mPFS) and median OS (mOS) were 40.6 m and 53.7 m, respectively. mPFS after 12 cycles of adjuvant TMZ (mPFS-TMZ12) for all 20 patients, Group A, and B were 26.8 m, 96.2 m, and 26.8 m (p=0.379 for latter 2), respectively. mOS after 12 cycles of adjuvant TMZ (mOS-TMZ12) were 40 m, not reached, and 27.2 m (p=0.080), respectively. Factors significantly associated with better PFS were young age, female, higher KPS, debulking resection, and no residual enhancing disease (NRD) at TMZ12, and were female, debulking resection, and NRD at TMZ12 with OS. CONCLUSIONS: A minor subset of GBM patients could continue adjuvant TMZ for 12 cycles without progression and benefited for better survival. In this cohort of patients, discontinuation of adjuvant TMZ after 12 cycles may not compromise their outcome, especially in those with no residual disease.

BACKGROUND: Glioblastoma (GBM) is poor-prognosis cancer and tumor recurrence is inevitable despite intensive chemoradiotherapy. Thus, insights into the mechanism of tumor recurrence are critical for improved patient treatment. Here, we describe our integrated genomic analyses using next-generation sequencing of the paired samples from initial and recurrent tumors. MATERIAL AND METHODS: We collected paired GBM samples in patients who recurred after temozolomide (TMZ) treatment. Mutation analysis of the cancer-related genes was performed using Ion Ampliseq Cancer Hotspot Panel v2. In addition, MGMT promoter methylation and expression of mismatch repair (MMR) protein such as MLH1, MSH2, MSH6, and PMS2 were analyzed by pyrosequencing and Western blotting, respectively. RESULTS: Sixty tumor samples from 29 patients were included in this study. Mutation acquisition of cancer-related genes was observed only in 12 (41%) patients while remaining 17 (59%) patients were mutationally stable even after TMZ treatment. Mutations were gained in 5 MGMT methylated tumors and 7 unmethylated. Remarkably, 70% of acquired mutations in MGMT methylated tumor were G:C>A:T at non-CpG sites whereas only 8% in MGMT unmethylated tumors. In mutation gain group, MMR expression decreased significantly after treatment (p=0.012~0.048). Furthermore, in contrast to MGMT unmethylated tumors, MGMT methylated tumors showed marked MMR inactivation (40% vs. 7.5%, p=0.078). CONCLUSION: We showed different types of the mutation acquisition after TMZ treatment according to MGMT status, providing further insights into the mechanism of TMZ resistance to improve treatment of the patients with GBM.

We report a case of a 51-year-old woman with newly diagnosed glioblastoma multiforme (GBM) who was treated with surgery followed by the standard concomitant temozolomide (TMZ) and radiotherapy (RT). Although TMZ is generally safe and well-tolerated, she developed a sudden onset of prolonged and severe thrombocytopenia as the most prominent event of pancytopenia during the combined treatment, leading to discontinuation of the combined therapy. Thrombocytopenia lasted for more than 2 months with intensive, intermittent platelet transfusions. A bone marrow aspiration and biopsy performed after recovery of severe suppression still revealed reduced number of megakaryocytes. O 6-methylguanine-DNA methyltransferase (MGMT) analyses showed methylated MGMT promoter in GBM, but unmethylated promoters in both peripheral blood leukocytes and bone marrow cells. This is the first report suggesting the irrelevance of MGMT status of normal hematopoietic cells to TMZ-induced severe thrombocytopenia and pancytopenia.

OBJECTIVE: To study the expression and function of L-type amino acid transporter 1 (LAT1), a major catalytic subunit of system L that is responsible for the transport of large neutral amino acids, including most essential amino acids, in concert with the covalently bound 4F2 heavy chain, and is implicated in tumorigenesis. METHODS: Human glioma cell lines and tumor specimens were analyzed for LAT1 expression using Western blotting and reverse transcription polymerase chain reaction analysis. The rate of neutral amino acid uptake was measured using L-[ 14 C] leucine. The proliferation and apoptosis rates were analyzed by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide and terminal deoxynucleotidyl transferase-mediated nick end-labeling assays, respectively, on inhibition of system L by 2-aminobicyclo-(2, 2, 1 )-heptane-2-carboxylic acid. The effects on proliferation and tumor growth caused by exogenously overexpressed LAT1 were similarly analyzed. RESULTS: LAT1 was expressed in most human high-grade gliomas and glioma cell lines at various levels, with more ubiquitous expression of 4F2 heavy chain. Glioma cells with high LAT1 expression exhibited a marked increase in the uptake rate of L- [14 C] leucine. 2-Aminobicyclo-(2, 2, 1)-heptane-2-carboxylic acid treatment not only suppressed deoxyribonucleic acid synthesis in association with the up-regulation of the cyclin-dependent kinase inhibitor p21 WAF1 but also enhanced apoptosis with caspase activation, thereby exerting both cytostatic and cytocidal effects in glioma cells with high LAT1 expression levels. Furthermore, overexpression of LAT1 in glioma cells with low endogenous LAT1 expression significantly enhanced the rates of tumor cell growth in athymic mice. CONCLUSION: LAT1, the major transporter of system L, is frequently expressed at higher levels in high-grade gliomas than in low-grade gliomas and brain tissues, and it may play an important role in enhancing the rates of tumor cell proliferation and growth in vivo.

Primary central nervous system lymphoma (PCNSL) is a rare malignancy confined to CNS. Despite low tendency of systemic dissemination, its prognosis is poor with median overall survival of 4 years when treated with standard of care high-dose methotrexate-based chemoradiotherapy. Despite majority of PCNSL is diffuse large B-cell lymphoma (DLBCL), its response to therapy and biological behavior differ from the systemic disease, necessitating detailed investigation of its pathogenesis and genetic alterations. Here we performed whole-exome sequencing (WES) on 41 PCNSL and paired normal specimens as well as RNA sequencing. Seven cases were classified as germinal center B-cell-like (GCB) subtype (17%), while 34 cases were non-GCB. Progression-free survival was significantly longer in cases with GCB subtype as in systemic DLBCL (p = 0.027). WES yielded sequencing data with a mean coverage of 158Χ with 98% of the targeted bases covered by ≥20 independent reads. We identified a total of 17,385 somatic mutations, of which 62% were nonsynonymous single nucleotide variations. The predominant nucleotide substitution was a C > T transition (57.8%), especially in the context of the sequence GCG. WES revealed a substantial extent of aberrant somatic hypermutation (aSHM) with a high frequency of nonsynonymous somatic mutations especially in PIM1 (90.2%) and BTG2 (65.9%). Genes mutated other than aSHM include MYD88 (85.4%), most of which being L265P activating mutation. These mutations were not associated with GCB/non-GCB subtypes. Notably, mutations in a number of genes related to the NF-κB signaling pathway were also prominent. Copy number aberration analysis identified gains in chromosomes 1q, 7, 12, and 18q, and a loss of 6q. These results suggest that MYD88 and PIM1 mutations may play an important role in PCNSL development regardless of GCB subtypes, and NF-κB pathway could be the therapeutic targets of this intractable disease.

ISN-Harrlem consensus guidelines proposed incorporation of molecular information into the diagnostic criteria of brain tumors. The current recommendation for diffuse glioma is to identify IDH mutations and subclassify them into either astrocytoma or oligodendroglioma using the 1p19q or ATRX status. However, a major challenge in this scheme is to stratify IDH-wt tumors. We analyzed a series of 759 adult diffuse gliomas consisted of 171 WHO grade II, 218 grade III and 370 grade IV tumors for the IDH1/2, 1p19q and TERT promoter status. The combined IDH/TERT classification divided the series into four groups with distinct histopathological profiles and outcome. The IDH/TERT co-mutated tumors (Group A, n = 154) mainly consisted of oligodendroglial tumors (78%) and mostly harbored 1p19q co-deletion (93%). The second group was composed of IDH-mutant/TERT-wt (Group B, n = 131) and enriched with astrocytomas (69%). The double-negative (IDH wt and TERT wt) group (Group C, n = 239) showed a mixed histology, GBM being the most common (62%), however all the other histologies were also present. Tumors with IDH-wt/TERT-mut (Group D, n = 235) were mostly GBM (80%) or AA(15%). Overall survival (OS) significantly differed across the four groups (A, Not reached; B, 79 months; C, 21 months; D, 16 months). WHO grade did not associate with OS in Group A, B and D, suggesting the homogenous nature of these groups respectively. On the contrary, lower grade tumors showed significantly longer survival than grade IV tumors (33 months vs. 17 months, p < 0.001) in Group C, suggesting that IDH-wt gliomas are biologically heterogeneous group. We showed that TERT promoter mutation is a useful diagnostic marker which can stratify both IDH-mutant and IDH-wt gliomas into prognostically distinct subgroups.

Germ cell tumors constitute a heterogeneous group that displays a broad spectrum of morphology. They often arise in testes; however, extragonadal occurrence, in particular brain, is not uncommon, and whether they share a common pathogenesis is unknown. We performed whole exome sequencing in 41 pairs of central nervous system germ cell tumors (CNS GCTs) of various histology and their matched normal tissues. We then performed targeted sequencing of 41 selected genes in a total of 124 CNS GCTs, 65 testicular germ cell tumors (tGCTs) and 8 metastatic GCTs to the CNS. The results showed that mutually exclusive mutations of genes involved in the MAPK pathway were most common (48.4 %), typically in KIT (27.4 %), followed by those in the PI3K pathway (12.9 %), particularly in MTOR (6.5 %), among the 124 CNS GCTs. Pure germinomas and non-germinomatous germ cell tumors (NGGCTs), as well as CNS and testicular GCTs, showed similar mutational profiles, suggesting that GCTs share a common molecular pathogenesis. Mutated MTOR identified in CNS GCTs upregulated phosphorylation of the AKT pathway proteins including AKT and 4EBP1 in nutrient-deprived conditions and enhanced soft-agar colony formation; both events were suppressed in a dose-dependent manner by addition of the MTOR inhibitor pp242. Our findings indicate that the dominant genetic drivers of GCTs regardless of the site of origin are activation of the MAPK and/or PI3K pathways by somatic point mutations. Mutated MTOR represents a potential target for novel targeted therapies for refractory GCTs.

Primary central nervous system lymphoma (PCNSL) is a rare malignancy confined to the central nervous system (CNS), and majority of PCNSL is pathologically classified as diffuse large B-cell lymphoma (DLBCL). We have now performed whole-exome sequencing for 41 tumor tissues of DLBCL-type PCNSL and paired normal specimens and also RNA-sequencing for 30 tumors, revealing a very high frequency of nonsynonymous somatic mutations in PIM1 (100 %), BTG2 (92.7 %), and MYD88 (85.4 %). Many genes in the NF-κB pathway are concurrently mutated within the same tumors. Further, focal deletion or somatic mutations in the HLA genes are associated with poor prognosis. Copy number amplification and overexpression of genes at chromosome 7q35 were both found to predict short progression-free survival as well. Oncogenic mutations in GRB2 were also detected, the effects of which in cultured cells were attenuated by inhibitors of the downstream kinases MAP2K1 and MAP2K2. Individuals with tumors positive for MYD88 mutations also harbored the same mutations at a low frequency in peripheral blood mononuclear cells, suggesting that MYD88 mutation-positive precancerous cells originate outside of the CNS and develop into lymphoma after additional genetic hits that confer adaptation to the CNS environment.

A hallmark of highly malignant human gliomas is their infiltration of the brain. We analyzed a large number of primary human glioma biopsies and found high levels of expression of an angiogenic regulator, angiopoietin-2 (Ang2), in the invasive areas, but not in the central regions, of those tumors. In the invasive regions where Ang2 was overexpressed, increased levels of matrix metalloprotease-2 (MMP-2) were also apparent. Consonant with these features, intracranial xenografts of glioma cells engineered to express Ang2 were highly invasive into adjacent brain parenchyma compared with isogenic control tumors. In regions of the Ang2-expressing tumors that were actively invading the brain, high levels of expression of MMP-2 and increased angiogenesis were also evident. A link between these two features was apparent, because stable expression of Ang2 by U87MG cells or treatment of several glioma cell lines with recombinant Ang2 in vitro caused activation of MMP-2 and acquisition of increased invasiveness. Conversely, MMP inhibitors suppressed Ang2-stimulated activation of MMP-2 and Ang2-induced cell invasion. These results suggest that Ang2 plays a critical role in inducing tumor cell infiltration, and that this invasive phenotype is caused by activation of MMP-2.

2000 Background: To establish whether personalized peptide vaccination (PPV) is clinically beneficial for human leukocyte antigen (HLA)-A24-positive glioblastoma multiforme (GBM) patients refractory to temozolomide (TMZ)-based therapy. Methods: From January 2012 to March 2016, 88 HLA-A24-positive GBM patients refractory to TMZ-based therapy from 20 Japanese hospitals were randomly assigned to receive PPV treatment (n = 58) or best supportive care (BSC) (n= 30) at a 2 to 1 ratio. Four peptides chosen from 12 peptide candidates based on pre-vaccination IgG levels specific to each peptide or 4 corresponding placebos were injected subcutaneously once weekly for 12 times at the first course followed by biweekly vaccinations until disease progression. The primary endpoint was overall survival (OS). Results: The primary endpoint was not met in this clinical trial. Unfavorable prognostic factors were performance status (PS) 3, higher plasma levels of pre-vaccination granulocyte macrophage-colony stimulating factor (GM-CFS), and PPV containing SART2-derived peptides. Therefore, 78 patients with PS of 0 to 2 (50 with PPV and 28 with BSC) were provided for the subgroup analysis. Among them, the median OS of 39 PPV patients (10.4 months, 95% CI, 7.8-12.0 months) who had either lower levels of GM-CSF ( < 0.9 pg/mL) or 4 peptide vaccinations that did not include SART2-derived peptides was significantly (p = 0.03) longer than that of the corresponding 19 BSC patients (6.8, 4.6-12.7). In contrast, the median OS of 10 PPV patients (4.1, 1.1-8.3) who had both higher levels of GM-CSF ( > 0.9 pg/mL) and 4 peptide vaccinations containing SART2-derived peptides was significantly (p = 0.01) shorter than that of the corresponding 9 BSC patients (not reached, 1.6-not reached). A single grade 3 adverse event was the only PPV-related adverse event of grade > 3 in this study. Conclusions: PPV monotherapy could be a new treatment modality for HLA-A24-positive GBM patients refractory to TMZ-based therapy, since this approach showed clinical benefit and safety under precision medicine-based pre-vaccination selection of appropriate patients. Clinical trial information: UMIN000006970.

Immunotherapy trials for glioblastoma (GBM) have some effects but the efficacy was limited, some because of the low immunogenicity and diverse antigens for GBMs. Personalized selection of suitable peptides for patients is one way to conquer this problem. We conducted serial series of clinical trials with 14 kinds of vaccine candidates (ITK-1) in patients with advanced cancers. Here we report our phase I results of ITK-1 in GBM and also introduce the trial design of phase III in GBM which is on-going. (Phase I) Twelve HLA-A-24 positive patients were enrolled from 8 Japanese hospitals. The dose escalation trial was conducted to determine safety and tolerability of ITK-1 peptides (at 1mg, 3mg, 5mg), however because of a dose limiting toxicity (injection site skin reaction) in another ITK-1 phase I trial for advanced prostate cancer, patients with 5mg dose was skipped or discontinued. No serious adverse drug reactions were observed. By analysis of intention to treat, two patients displayed PR, 5 SD and 5 PD by WHO criteria. The PFS rate at 6 months was 16.7%. Median OS from registration was 10.6 months. (Phase III) Based on the phase I trial, phase III trial is on-going. GBM patients refractory or recurrence after standard initial TMZ-radiation treatment were enrolled. The multi-institutional trial are conducting under IRB approval of each institutes and written informed consents from the patients and/or responsible relatives. HLA-A24 positive patients receive peptide vaccine (3mg/1.5ml) or placebo with selected 2 to 4 subcutaneous injection once weekly in total 12 times at the first course. At the second to twenty course, peptide vaccine or placebo is administered biweekly. Patients were randomly assigned (2: 1) to receive relevant peptides or placebo and both arms were under best supportive care. No other chemotherapy, immunotherapy nor radiotherapy are allowed. The primary endpoint is OS and secondary endpoints includes survival rates at 12 month, objective tumor response, immune responses and PFS. A total of 90 cases were registered and the results will be open by June 2017. So far we do not experience serious side effects, excluding one case of pulmonary embolus. Overall survival of all cases (both vaccine and placebo arms together) from registration is 8.4 months.

Intorduction: Recent comprehensive genomic analysis have revealed many genetic alterations in diffuse gliomas, but few markers besides IDH and 1p19q are utilized for diagnosis in the CNS WHO 2016. In particular, diagnostic and/or prognostic markers for IDH-wild tumors are not defined, except for H3.1/3.3. TERT promoter mutation frequently occurs in GBMs among IDH-wild tumors, but its prognostic impact remains controversial. In order to evaluate the influence of TERT, we analyzed a large cohort of IDH wild type tumors. Materials and Methods: One hundred fifty-one grade II-III and 453 GBM cases without IDH mutations were included. All GBM cases were treated with standard radiotherapy and temozolomide. Molecular statuses including IDH, MGMT and TERT were assessed by pyrosequencing and/or Sanger sequencing using frozen tumor tissues for all cases. The survival data were analyzed with the log-rank test and univariate and multivariate Cox regression analyses.Results: In grade II-III cases, TERT mutations were observed in 54% cases and associated with shorter survival (16.1 months for TERT-mutated vs. 34.8 months for TERT-wild cases, p

Low-grade gliomas often undergo malignant progression, and these transformations are a leading cause of death in patients with low-grade gliomas. However, the molecular mechanisms underlying malignant tumor progression are still not well understood. Recent evidence indicates that epigenetic deregulation is an important cause of gliomagenesis; therefore, we examined the impact of epigenetic changes during malignant progression of low-grade gliomas. Specifically, we used the Illumina Infinium Human Methylation 450K BeadChip to perform genome-wide DNA methylation analysis of 120 gliomas and four normal brains. This study sample included 25 matched-pairs of initial low-grade gliomas and recurrent tumors (temporal heterogeneity) and 20 of the 25 recurring tumors recurred as malignant progressions, and one matched-pair of newly emerging malignant lesions and pre-existing lesions (spatial heterogeneity). Analyses of methylation profiles demonstrated that most low-grade gliomas in our sample (43/51; 84%) had a CpG island methylator phenotype (G-CIMP). Remarkably, approximately 50% of secondary glioblastomas that had progressed from low-grade tumors with the G-CIMP status exhibited a characteristic partial demethylation of genomic DNA during malignant progression, but other recurrent gliomas showed no apparent change in DNA methylation pattern. Interestingly, we found that most loci that were demethylated during malignant progression were located outside of CpG islands. The information of histone modifications patterns in normal human astrocytes and embryonal stem cells also showed that the ratio of active marks at the site corresponding to DNA demethylated loci in G-CIMP-demethylated tumors was significantly lower; this finding indicated that most demethylated loci in G-CIMP-demethylated tumors were likely transcriptionally inactive. A small number of the genes that were upregulated and had demethylated CpG islands were associated with cell cycle-related pathway. In summary, we demonstrated that characteristic DNA demethylation occurred during malignant progression of a subset of low-grade gliomas. The mechanisms underlying and consequences of such DNA demethylation should be studied further.

BACKGROUND: Intracranial germ cell tumors (iGCTs) are rare in the Western countries, however they are the second most common brain tumors in patients under 14 in Japan. Unlike other common pediatric brain tumors, the biology of iGCTs is largely unknown. METHODS: We performed a whole exome sequencing in a large series of iGCTs to elucidate their molecular pathogenesis. A total of 198 germ cell tumors (GCTs) including 133 iGCTs (69 pure germinomas, 56 NGGCTs and 8 metastatic tumors) as well as 65 testicular germ cell tumors (tGCTs) (39 seminomas and 26 non-seminoma GCTs) were collected from 13 centers participating in the Intracranial Germ Cell Tumor Consortium in Japan. Somatic mutations in all coding exons were investigated by whole exome sequencing (WES) in 41 tumors and the matched normal DNAs. Based on the WES data, 41 candidate genes were selected according to the frequency and/or significance of the mutations found. All coding exons of these 41 genes spanning over 160kb were PCR-amplified in a further 157 GCTs and sequenced using the IonTorrent system. The results were integrated with the patients' clinical information that was available for 124 iGCT patients. RESULTS: On average, 15.4 non-synonymous somatic mutations were observed in each tumor, ranging from 1 to 140 by WES in 41 iGCTs. The combined WES and IonTorrent screenings showed that KIT was the most frequently mutated gene in both iGCTs (27%) and tGCTs (18%). MTOR was the second most frequently mutated also in both iGCTs (7%) and tGCTs (6%). RAS mutations (KRAS, HRAS, NRAS) were altogether found in 13% of iGCTs and 12% of tGCTs. These mutations were mutually exclusive to each other and also to KIT mutations. Collectively, the genes involved in the MAPK pathway (e.g., KIT, RAS, NF1) and the PI3K/MTOR pathway (e.g., MTOR, PTEN) were mutated in 44% and 13% of all GCTs. Among the iGCTs, these alterations were significantly more common among pure germinomas than NGGCTs. The mutated MTOR protein was shown to have increased kinase activity, which was suppressed by specific MTOR inhibitors. CONCLUSIONS: Our comprehensive mutational genomic analysis of GCTs revealed that alterations of the MAPK and/or PI3K/MTOR pathways play a critical role in the pathogenesis of both iGCTs and tGCTs, although the extent of their involvement depends on the histopathological subtypes. Our findings will hopefully lead to the development of a targeted therapy for treatment-resistant iGCTs. SECONDARY CATEGORY: Tumor Biology.

Glioblastoma(GBM)is the most malignant and frequent primary brain tumor. The current standard of care consists of maximum safe resection and radiotherapy with concomitant and subsequent temozolomide(TMZ)treatment. With this treatment plan, the prognosis of patients with GBM remains dismal, with a 5-year survival rate of10%; thus development of effective, novel therapies is needed. Bevacizumab(Bev, Avastin®)is a humanized monoclonal antibody against vascular endothelial growth factor(VEGF), one of the major potent angiogenic factors for the growth of human cancers, including GBM. Bev has been shown to effectively shrink enhancing lesions of recurrent GBM and decrease symptom burden and brain edema. These positive results led to its approval for malignant glioma treatment in June 2013 in Japan. Two double-blind, placebo-controlled, randomized phase III studies of Bev in newly diagnosed GBM were conducted to verify its efficacy as a first-line therapy used in combination with TMZ. The results, which were reported at the American Society for Clinical Oncology(ASCO)meeting in June 2013, failed to show an increase in overall survival, despite prolongation in progression-free survival. These results led to many unsolved issues regarding the use of Bev for the treatment of GBM. We discuss these problems in this paper and highlight our institutional experience with Bev monotherapy for recurrent high-grade gliomas.

In progressive multifocal leukoencephalopathy, JC virus–infected oligodendroglia display 2 distinct patterns of intranuclear viral inclusions: full inclusions in which progeny virions are present throughout enlarged nuclei and dot-shaped inclusions in which virions are clustered in subnuclear domains termed “promyelocytic leukemia nuclear bodies” (PML-NBs). Promyelocytic leukemia nuclear bodies may serve a scaffolding role in viral progeny production. We analyzed the formation process of intranuclear viral inclusions by morphometry and assessed PML-NB alterations in the brains of 2 patients with progressive multifocal leukoencephalopathy. By immunohistochemistry, proliferating cell nuclear antigen was most frequently detected in smaller nuclei; cyclin A was detected in larger nuclei. This suggests an S-to-G2 cell cycle transition in infected cells associated with nuclear enlargement. Sizes of PML-NBs were variable, but they were usually either small speckles 200 to 400 nm in diameter or distinct spherical shells with a diameter of 1 μm or more. By confocal microscopy, JC virus capsid proteins were associated with both small and large PML-NBs, but disruption of large PML-NBs was observed by ground-state depletion fluorescence nanoscopy. Clusters of progeny virions were also detected by electron microscopy. Our data suggest that, in progressive multifocal leukoencephalopathy, JC virus produces progeny virions in enlarging oligodendrocyte nuclei in association with growing PML-NBs and with cell cycle transition through an S-to-G2-like state.

OBJECTIVE: Sodium butyrate (SB), a differentiation-inducing agent, has been demonstrated to inhibit cellular proliferation in a number of human cell lines. Its precise mechanisms remain to be clarified, however. We investigated molecular mechanisms of SB-induced growth suppression as well as the effects of SB on the invasiveness of human glioma cells. METHODS: Human glioma U87MG and U251MG cells were treated with 1 or 2 mmol/L SB for 48 hours, and the inhibition of cell growth was assessed by spectrophotometric analysis. Cell cycle analysis was carried out by the 5-bromo-2'-deoxyuridine incorporation method, and expression of cell cycle-regulatory proteins was determined by immunoblotting. In addition, invasiveness was assessed using a Transwell chamber (Iwaki, Tokyo, Japan) with extracellular matrix substrate fibronectin or laminin (Iwaki). RESULTS: SB treatment resulted in significantly suppressed proliferation of both U87MG and U251MG cells in a dose-dependent manner. It inhibited the G 1 -S transition, which was associated with increased expression of p21 and cyclin D1 and reduced pRb phosphorylation. Treatment with antisense oligonucleotide for Rb abrogated SB-induced G 1 arrest, p21 up-regulation was independent of the p53 status of the glioma cells. SB treatment also inhibited invasiveness on fibronectin and laminin. CONCLUSION: Our results indicate that SB may suppress the growth of human glioma cells through modulation of cell cycle progression and also may affect their invasiveness on extracellular matrix substrates, which suggests that SB may be a useful therapeutic agent in treating multiple aspects of malignant gliomas.

Innate and acquired resistance to chemotherapy and radiation therapy has been a major obstacle for clinical oncology. One potential adjunct to such conventional treatments is direct induction of cell death by activation of death receptor-mediated apoptosis. TRAIL (tumor necrosis factor (TNF)-related apoptosis inducing ligand), a recently identified member of the growing TNF superfamily, binds to its cognate "death" receptors DR4 and DR5 as well as "decoy" receptors DcR1 and DcR2. Upon binding, rapid apoptosis is enacted in a variety of human cancer cell lines independent of p53 status, but not in normal cell lines. TRAIL treatment results in significant growth suppression of TRAIL-sensitive human cancer xenografts in mice. Furthermore, combination treatment of TRAIL with genotoxic chemotherapeutic agents synergistically suppresses growth of tumor xenografts which are otherwise resistant to treatment with TRAIL or chemotherapy alone. Unlike the other death ligands TNF-alpha or FasL, systemic administration of soluble human TRAIL does not cause toxicity in mice and non-human primates. While further studies are needed to evaluate the possible cytotoxicity of TRAIL especially for human hepatocytes, indications are increasing that TRAIL may be a novel therapeutic agent for human cancer.

Malignant gliomas are among the most lethal and intractable of human tumors and drug resistance is one of the major obstacles to their successful treatment. Recent advances in the molecular biology and genetics of human cancers provide a detailed understanding of cellular and molecular responses to chemotherapy and how drug resistance may develop. Several oncogenes and tumor suppressor genes have been shown to confer resistance to tumor cells and should, therefore, provide novel and defined targets for cancer treatment. In addition to overcoming cellular resistance, special efforts to increase drug delivery to glial tumors need to be pursued because of the relatively unique problem of the blood-brain barrier. Treatments aimed at these targets will likely benefit from combined therapies including surgery, traditional chemotherapy and targeted disruption of other physiological processes such as angiogenesis. Copyright 1999 Harcourt Publishers Ltd.

Deregulation of signaling by the epidermal growth factor receptor (EGFR) is common in human malignancy progression. One mutant EGFR (variously named DeltaEGFR, de2-7 EGFR, or EGFRvIII), which occurs frequently in human cancers, lacks a portion of the extracellular ligand-binding domain due to genomic deletions that eliminate exons 2 to 7 and confers a dramatic enhancement of brain tumor cell tumorigenicity in vivo. In order to dissect the molecular mechanisms of this activity, we analyzed location, autophosphorylation, and attenuation of the mutant receptors. The mutant receptors were expressed on the cell surface and constitutively autophosphorylated at a significantly decreased level compared with wild-type EGFR activated by ligand treatment. Unlike wild-type EGFR, the constitutively active DeltaEGFR were not down-regulated, suggesting that the altered conformation of the mutant did not result in exposure of receptor sequence motifs required for endocytosis and lysosomal sorting. Mutational analysis showed that the enhanced tumorigenicity was dependent on intrinsic tyrosine kinase activity and was mediated through the carboxyl terminus. In contrast with wild-type receptor, mutation of any major tyrosine autophosphorylation site abolished these activities suggesting that the biological functions of DeltaEGFR are due to low constitutive activation with mitogenic effects amplified by failure to attenuate signaling by receptor down-regulation.

Two double blind, placebo-controlled, and randomized phase III studies were conducted, and the results including OS’s were reported at the ASCO Meeting in June 2013, which was the beginning of confusion surrounding this topic. This is a review article not only summarizing the previous evidence, but also looking beyond.

Aberrant activation of EGFR in human cancers promotes tumorigenesis through stimulation of AKT signaling. Here, we determined that the discoidina neuropilin-like membrane protein DCBLD2 is upregulated in clinical specimens of glioblastomas and head and neck cancers (HNCs) and is required for EGFR-stimulated tumorigenesis. In multiple cancer cell lines, EGFR activated phosphorylation of tyrosine 750 (Y750) of DCBLD2, which is located within a recently identified binding motif for TNF receptor-associated factor 6 (TRAF6). Consequently, phosphorylation of DCBLD2 Y750 recruited TRAF6, leading to increased TRAF6 E3 ubiquitin ligase activity and subsequent activation of AKT, thereby enhancing EGFR-driven tumorigenesis. Moreover, evaluation of patient samples of gliomas and HNCs revealed an association among EGFR activation, DCBLD2 phosphorylation, and poor prognoses. Together, our findings uncover a pathway in which DCBLD2 functions as a signal relay for oncogenic EGFR signaling to promote tumorigenesis and suggest DCBLD2 and TRAF6 as potential therapeutic targets for human cancers that are associated with EGFR activation.

A mutant epidermal growth factor receptor (DeltaEGFR) containing a deletion of 267 amino acids from the extracellular domain is common in human glioblastomas. We have previously shown that the mutant receptor fails to bind EGF, is constitutively phosphorylated, and confers upon U87MG glioblastoma cells expressing it (U87MG. DeltaEGFR), an increased ability to form tumors in mice. Here we demonstrate that the constitutively phosphorylated DeltaEGFR enhances growth of glioblastoma cells through increased activity of Ras: 1) there was an increase in the proportion of Ras present in the GTP-bound form, and 2) introduction of neutralizing anti-Ras 259 antibodies into U87MG and U87MG.DeltaEGFR cells by microinjection inhibited DNA synthesis to the same low level in both cell populations. We also show that the truncated EGF receptor constitutively associates with the adapter proteins Shc and Grb2 which are involved in the recruitment of Ras to activated receptors. Several derivatives of DeltaEGFR containing single, or multiple mutations at critical autophosphorylation sites were constructed and used to demonstrate that the major Shc binding site is Tyr-1148, and that Grb2 association occurs primarily through Tyr-1068. We conclude that the increased tumorigenic potential of glioblastoma cells expressing the truncated EGF receptor is due at least in part to Ras activation presumably involving the Shc and Grb2 adapter proteins.

BACKGROUND Two rare cases of triple primary malignant neoplasms (PMN), including malignant brain tumors, which were glioblastoma multiformes, are described. METHODS The clinical characteristics and underlying genetic alterations in triple or more PMN, including malignant brain tumors are discussed with intensive review of the literature. RESULTS The first patient, a 77-year-old male, suffered metachronously from tubular adenocarcinoma of the stomach, transitional cell carcinoma of the bladder, and glioblastoma in the brain. This glioblastoma had loss of heterozygosity in exons 7-8 in p53 gene. The second patient, a 68-year-old male, developed papillary adenocarcinoma of the lung, adenocarcinoma of the rectum, and glioblastoma in the brain during a period of 7 years. In 42 such cases described in the literature, age distribution demonstrated two characteristic peaks, one in the third decade and the other over 50 years of age. The younger group consisted mainly of Turcot's syndrome, and of a case of Li-Fraumeni familial cancer syndrome. On the other hand, neither of these hereditary cancer syndromes were contained in the elder group. Regarding the site of PMN, colorectal cancers were associated most frequently with malignant brain tumors, followed by stomach cancers, and thyroid cancers. Malignant brain tumors, mostly glioblastoma multiforme, tend to occur as the last tumor of triple or more PMN. CONCLUSIONS These results suggest that genetic background might play an important role in tumorigenesis of PMN in the younger group, whereas epigenetic factors would be more important in the older group. Characteristic organ association and factors influencing carcinogenesis, such as aging, environmental carcinogens, and underlying genetic alterations in these tumors are further discussed.

BACKGROUND Glioblastoma multiforme represents one of the most malignant forms of primary intracranial tumors, often intractable to multimodality of treatment including chemotherapy. The unsatisfactory results of chemotherapy are chiefly attributed to chemoresistance. Since various molecules that could confer drug resistance have been elucidated, screening of the amount of such molecules in the tumor cells could provide possibilities for predicting their chemoresistance beforehand and help select more effective drugs. METHODS We present a 45-year-old woman with recurrent glioblastoma multiforme in the cerebellum and invading the brain stem, treated successfully by postoperative chemotherapy. In this patient, anticancer drugs were determined by measurements of mRNA expression of chemoresistance-related genes, such as O6-methylguanine-DNA methyltransferase (MGMT), mdr1, glutathione S-transferase (GST)-pi, and metallothionein (MT) in the resected tumor. RESULTS Northern blot analysis demonstrated the moderate mRNA level of MGMT, a major molecule causing ACNU (1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitroso ure a hydrochloride) resistance. On the other hand, expression levels of mdr1 which codes the P-glycoprotein responsible for multidrug resistance, and GST-pi, a detoxification enzyme, were low. Transcript of MT, another thiol containing molecule for cellular detoxification possibly associated with cisdiamminedichloroplatinum(II) (CDDP) resistance, was only faintly detectable. Postoperatively, the patient was treated initially with intravenous administration of ACNU and etoposide (VP16), resulting in a minor response of tumor regression. For maintenance therapy, we changed ACNU to CDDP according to the findings of the Northern blot analysis. Consequently, the residual tumor showed a marked response and almost disappeared after two courses of systemic chemotherapy with CDDP and VP16. CONCLUSIONS The successful tumor regression in this case suggests that Northern blot analysis on expression of these chemoresistance-related genes in tumor tissues could provide beneficial information for determination of optimal anticancer agents to improve the efficacy of chemotherapy.

2003Background: Whether salvage stereotactic radiosurgery (SRS) alone is effective for patients with brain metastases (BM) is not yet clarified, although clinical benefits such as better preservation of cognitive function and a shorter treatment period are reported with SRS compared to whole-brain radiation therapy (WBRT). We conducted a non-inferiority, randomized study of the effectiveness of salvage SRS for residual and recurrent tumors after surgical resection in comparison to tumor resection plus WBRT. Methods: Patients between 20-79 years with ECOG performance status (PS) 0-3 and ≤4 BM with only one lesion ≥3 cm in diameter having been surgically resected were eligible. Within 21 days after surgery, patients were randomized to WBRT or salvage SRS for residual and recurrent tumors. The primary end point was overall survival (OS) and the secondary end points were intracranial progression-free survival (IC-PFS), adverse events, and proportion of non-worsening in PS and Mini Mental Status Examination (M...

Glioblastoma (GBM) is one of the worst cancers in terms of prognosis. Standard therapy consists of resection with concomitant chemoradiotherapy. Resistance to nimustine hydrochloride (ACNU), an alkylating agent, has been linked to methylguanine DNA methyltransferase (MGMT). Daily administration of procarbazine (PCZ) has been reported to decrease MGMT activity. This study investigated the efficacy of ACNU + PCZ compared to ACNU alone for GBM and anaplastic astrocytoma (AA). Patients (20–69 years) who had newly diagnosed AA and GBM were randomly assigned to receive radiotherapy with ACNU alone or with ACNU + PCZ. The primary endpoint was overall survival (OS). This was designed as a phase II/III trial with a total sample size of 310 patients and was registered as UMIN-CTR C000000108. After 111 patients from 19 centers in Japan were enrolled, this study was terminated early because temozolomide was newly approved in Japan. The median OS and median progression-free survival (PFS) with ACNU alone (n = 55) or ACNU + PCZ (n = 56) in the intention-to-treat population were 27.4 and 22.4 months (p = 0.75), and 8.6 and 6.9 months, respectively. The median OS and median PFS of the GBM subgroup treated with ACNU alone (n = 40) or ACNU + PCZ (n = 41) were 19.0 and 19.5 months, and 6.2 and 6.3 months, respectively. Grade 3/4 hematologic adverse events occurred in more than 40 % of patients in both arms, and 27 % of patients discontinued treatment because of adverse events. The addition of PCZ to ACNU was not beneficial, in comparison with ACNU alone, for patients with newly diagnosed AA and GBM.

Recurrent glioblastoma after initial radiotherapy plus concomitant and adjuvant temozolomide is problematic. Here, patients with temozolomide-refractory high-grade gliomas were treated with bevacizumab (BV) and evaluated using apparent diffusion coefficient (ADC) for response. Nine post-temozolomide recurrent or progressive high-grade glioma patients (seven with glioblastoma and two with anaplastic astrocytoma) were treated with BV monotherapy. Average age was 57 years (range, 22–78), median Karnofsky Performance Scale (KPS) was 70 (30–80) and median BV line number was 2 (2–5). Two had additional stereotactic radiotherapy within 6 months prior to BV. Magnetic resonance (MR) imaging after BV therapy was performed within 2 weeks with calculation of mean ADC (mADC) values of enhancing tumor contours. Post-BV treatment MR imaging showed decreased tumor volumes in eight of nine cases (88.9 %). Partial response was obtained in four cases (44.4 %), four cases had stable disease, and one had progressive disease. Of 15 evaluable enhancing lesions, 11 shrank and four did not. Pretreatment mADC values were above 1100 (10−6 mm2/s) in all responding tumors, while all non-responding lesions scored below 1100 (p = 0.001). mADC decreased after the first BV treatment in all lesions except one. KPS improved in four cases (44.4 %). Median progression-free survival and overall survival for those having all lesions with high mADC (>1100) were significantly longer than those with a low mADC (

Over the last decade, significant progress has been made in understanding glioma on a molecular level. However, optimal incorporation of molecular markers into clinical care is still controversial. Here, the potential utility of genetic alterations found in gliomas in refining histological diagnosis, prognosis, and predictive values for treatment selection is reviewed. Among all, O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation, 1p/19q codeletion, and isocitrate dehydrogenase 1 (IDH1) mutations have been identified as favorable prognostic markers. MGMT promoter methylation is the only potential predictive marker for response to temozolomide and alkylating agents in glioblastoma (GBM), but it is not of assistance in diagnostics. IDH1 mutations and 1p/19q codeletion are also useful for classifying and grading gliomas, since 1p/19q codeletion is tightly linked to oligodendroglial lineage, and IDH1 mutations are restricted to grade II/III gliomas, while not to primary GBM. BRAF fusion is a good marker for pilocytic astrocytoma. High-throughput profiling techniques for gene expression and epigenetic modification have provided new subtype classifications for GBM as well as lower grade gliomas, which may be of prognostic and predictive values. Efforts to identify molecular markers that predict the benefits of novel molecularly targeted treatments will enable better patient stratification and individualization of treatment.

Two hallmarks of glioblastoma multiforme, the most common malignant brain cancer in humans, are aggressive growth and the ability of single glioma cells to disperse throughout the brain. These characteristics render tumors resistant to current therapies and account for the poor prognosis of patients. Although it is known that oncogenic signaling caused by overexpression of genes such as PDGFRA is responsible for robust glioma growth and cell infiltration, the mechanisms underlying glioblastoma malignancy remain largely elusive. Here, we report that PDGFR\ensuremath? signaling in glioblastomas leads to Src-dependent phosphorylation of the guanine nucleotide exchange factor Dock180 at tyrosine 1811 (Dock180(Y1811)) that results in activation of the GTPase Rac1 and subsequent cell growth and invasion. In human glioma cells, knockdown of Dock180 and reversion with an RNAi-resistant Dock180(Y1811F) abrogated, whereas an RNAi-resistant Dock180(WT) rescued, PDGFR\ensuremath?-promoted glioma growth, survival, and invasion. Phosphorylation of Dock180(Y1811) enhanced its association with CrkII and p130(Cas), causing activation of Rac1 and consequent cell motility. Dock180 also associated with PDGFR\ensuremath? to promote cell migration. Finally, phosphorylated Dock180(Y1811) was detected in clinical samples of gliomas and various types of human cancers, and coexpression of phosphorylated Dock180(Y1811), phosphorylated Src(Y418), and PDGFR\ensuremath? was predictive of extremely poor prognosis of patients with gliomas. Taken together, our findings provide insight into PDGFR\ensuremath?-stimulated gliomagenesis and suggest that phosphorylated Dock180(Y1811) contributes to activation of Rac1 in human cancers with PDGFRA amplification.