No abstract

Single copy gain of 1q is associated with biological features of pediatric gliomas, and is a negative prognostic marker in patients with those tumors.

Abstract. Temozolomide constitutes current standard of care for adult patients with high-grade gliomas. However, results for pediatric gliomas are rather disappointing. In order to investigate the molecular differences between pediatric and adult gliomas that could affect sensitivity to temozolomide, we studied 23 pediatric non-ependymal, non-pilocytic gliomas in comparison to 59 consecutive adult gliomas for the expression of O 6 -methylguanine methyltransferase (MGMT) and the DNA mismatch repair protein, mutS homolog 6 (MSH6) by immunohistochemistry, as well as for the presence or absence of promoter methylation of the MGMT gene by methylationspecific PCR. The expression of MGMT in pediatric gliomas was significantly higher than in adult gliomas, as shown by immunohistochemistry (p=0.00004). This association was conserved if statistical analysis was carried out only in astrocytic tumors (diffuse astrocytoma, anaplastic astrocytoma and glioblastoma, p=0.00007), or in oligodendroglial tumors (oligodendroglioma and anaplastic oligodendroglioma, p=0.020). Although methylation-specific PCR was successfully performed only in 15 pediatric gliomas, it also showed a trend toward less frequent methylation in pediatric as opposed to adult gliomas (p=0.242). MSH6 was almost equally expressed in pediatric and adult gliomas. Pediatric gliomas appear to have a distinct molecular profile associated with resistance to temozolomide. Higher expression of MGMT and a trend toward less frequent methylation of the promoter region of MGMT gene may partly account for relative resistance to temozolomide in pediatric gliomas as compared to adult gliomas. IntroductionTemozolomide, an oral methylating agent, has better activity and less toxicity than conventional agents, including nitrosoureas in the treatment of gliomas (1,2). Indeed, concomitant and adjuvant temozolomide has improved progression-free survival and overall survival compared to radiotherapy alone in adult patients with newly diagnosed supratentorial glioblastoma, and constitutes current standard of care for those patients (3,4). Nowadays, the majority of clinical trials for gliomas comprises protocols, including temozolomide. However, the efficacy of temozolomide is virtually based on reports on adult gliomas, and results for pediatric gliomas are rather disappointing. Verschuur et al treated 20 children with recurrent high-grade gliomas, including 11 grade III and 8 grade IV gliomas. Progression-free survival at 6 months was 18 and 12.5% for each grade (5). Those figures are less favorably compared to those reported in adult studies (1,2). Ruggiero et al and Lashford et al also reported lower response rate to temozolomide in recurrent pediatric, high-grade gliomas as compared to adult gliomas (6,7). Moreover, in a previous phase II trial (ACNS0126) for newly diagnosed pediatric high-grade gliomas, chemoradiotherapy with temozolomide only provided comparable results to the historical control with BCNU (8).Temozolomide rapidly hydrolyzed into 5-amino-1H-imidazole-4-carboxam...

Neurosurgeons perform tumor resection based on their tactile perception. However, many years of experience and training are required to appropriately differentiate tumor tissue from surrounding parenchymal tissue. It was reported that the stiffness of human cancer tissue strongly correlates with pathological tissue and it can be used as a biomarker. Comprehensive analysis also revealed that the molecular expression differs greatly between hard and soft tumors.Haptics technology measures and uses the stimulus that causes the sensation as a physical quantity. Force and tactile sensation is a sensation caused by mechanical contact with an object. Real Haptics is our main research field, which is a general term for technologies that quantify and utilize the force-tactile stimuli generated by contact with objects that exist in the real world and / or the virtual world.We have developed a microsurgical forceps equipped with haptics technology to differentiate tumor tissue from surrounding brain tissue during tumor dissection. We generated and used three glioblastoma cell lines (SF126, U87, U251) expressing proteins of firefly luciferase and mCherry. Each cell line was transplanted into forebrain of 5 nude mice. Tumor progression was regularly monitored with In Vivo Imaging System (IVIS) and mice were euthanized at the appropriate stage. Tumor and normal brain stiffness were measured by using the Master-slave integrated haptic forceps device. Importantly, all of the three glioblastomas were shown to be harder than the normal brain (p=0.047). The median stiffness of each tissue was as follows. Normal brain (n=15): 149.98 N/m, SF126 (n=5): 207.70 N/m, U87 (n=5): 214.40 N/m, U251 (n=5): 188.86 N/mThis pilot study showed that brain tumors could be differentiated by their stiffness from normal brain, and the forceps equipped with haptics technology might help the neurosurgeons to dissect tumor margin along the appropriate plane.

To date, few clinical observations have been reported for changes of alternative angiogenic factors (other than vascular endothelial growth factor [VEGF]) in human gliomas under bevacizumab (Bev). The elucidation of the mechanism of action and resistance is imperative to overcome resistance to Bev and develop a more effective therapy. This study aims to investigate the status and change of alternative angiogenic factors regarding Bev usage.The present study used 56 glioblastoma tissues obtained at 3 different settings: tumors of initial resection (naive Bev group), tumors resected following Bev therapy (effective Bev group), and recurrent tumors after Bev therapy (refractory/autopsied Bev group). The expression of alternative angiogenic factors including basic fibroblast growth factor (bFGF), placental growth factor (PlGF), Angiopoietin1 (Ang-1), Angiopoietin2(Ang-2) and EphrinA2 were investigated via immunohistochemistry. In large tumor vasculature (diameter >15μm), the expression of PlGF was significantly higher in the effective Bev group than naive Bev group. The expression of Ang-2 was persistently suppressed in the refractory/autopsied Bev group. In microtumor vasculature (diameter <15μm), the expression of Ang-2 was higher in the effective group than naive Bev group. The status of PlGF was similar among these three groups.We provide the first clinicopathological evidence of the status of alternative angiogenic pathway after the Bev usage. These in situ observations will help to optimize therapy.