Associations of pathological diagnosis and genetic anomalies of meningiomas with the embryological origins of the meninges
Japanese study of
Summary
Certain driver's mutations and certain pathological diagnoses are associated with the anatomical site of meningioma , on the basis of which the meninges have different embryological origins.
We have hypothesized that the mutations and pathological diagnoses of meningiomas are associated with different embryological origins.
We exhaustively evaluated the associations between the location of the tumor, the pathological diagnosis (histological type) and the genetic alterations, including the mutations of AKT1, KLF4, SMO, POLR2A and NF2 and the deletion 22q in 269 cases of meningiomas .
Depending on the embryological origin of the meninges , the localizations of the tumors were as follows: neural crest, paraxial mesoderm and dorsal mesoderm. Tumors from the dura of certain embryological origins had pathological diagnoses and a ratio of significantly different genetic anomalies. For example, driver genetic mutations with AKT1, KLF4, SMO , and POLR2A , were significantly associated with paraxial mesodermal origin ( p = 1.7 × 10 -10 ).
On the other hand, the meningiomas with mutations associated with the NF2 were significantly associated with the origin of the neural crest ( p = 3.9 × 10 –12 ). During the analysis of recurrences, no difference was observed according to the embryological origin.
POLR2A mutation was a risk factor for tumor recurrence ( p = 1.7 × 10 −2 , relative risk 4.08, 95% confidence interval 1.28-13.0). The evaluation of the embryological origin of the meninges could provide new information on the mechanism of meningiomas.
Introduction
Meningiomas are the most common primary intracranial tumors, representing 20 % of all of these tumors . About 69 % of meningiomas are mild (Grade I of WHO), while 29 % are atypical (Grade II of WHO) and 2 % are clever (Grade III of WHO) (1). Previous studies have suggested an association between the location of meningioma and the histological grade, non -cranial meningiomas with more aggressive biological behavior (2,3,4,5,6).
Molecular genetics research has revealed mutations in the NF2 in around 40 to 60 % of sporadic meningiomes (6.7). Recent studies have reported Traf7, KLF4, AKT1, SMO, PIK3CA, and POLR2A , all mutually exclusive of NF2 (8,9,10,11,12,13).
In these reports, the NF2 and/or the loss of chromosome 22 are predominant in meningiomas from cerebral convexity and cerebellar hardness and in the spinal canal (8,12,14,15). By comparing the various locations of the skull base, most non -NF2 NF2 mutations or a loss of chromosome 22 (7,8,12,16,19,19). Thus, genetic mutations can be potentially associated with anatomical sites.
The meninges could have different embryological origins depending on the anatomical site. Many studies on the development of meninges in humans strongly indicate three sources of embryogenesis: the neural crest, the paraxial mesoderm and the dorsal mesoderm (20,21,22,23,24,25). These differences in the embryological origin of the meninges are associated with the pathophysiology of various diseases (26,27).
We have hypothesized that conductive mutations and pathologies linked to meningiomas are associated with meningeal origin . We have modified the concept of location of the tumor as a function of the embryological origin of the different meningeal parts to verify this hypothesis. Then, we exhaustively evaluated the associations between the location of the tumor (embryological origin), the pathological diagnosis (histological type) and the mutations of the driver, in particular the mutations AKT1, KLF4, SMO, POLR2A and NF2 .
Finally, we evaluated the factors affecting tumor recurrence , such as clinical parameters, embryological origins, pathological diagnosis and genetic mutations.
Results
Characteristics of patients
A total of 499 patients with meningioma having undergone surgery at the University of Tokyo hospital in Japan, between January 2000 and June 2017 were included in this study. Among them, 269 patients adhered to the criteria for the inclusion of the study . This study included 192 women (71 %) and 77 men (29 %) . The average age of patients was 58.0 years (interval: 0.1-81.2 years) and the average duration of follow-up was 50.4 months (interval: 1-199) (see Table 1 in the link ).
Pathological diagnosis and embryological origins of the meninges
Table 1 provides raw data concerning the location of tumors, genetic status and clinico-histopathological characteristics.
Figure 1A-C shows a schematic representation of the spatial distribution of the embryological origins of the meninges, based on previous relationships. The meninges originating in the neural ridge are in purple, those who originally originally the paraxial mesoderm are green, and those originating in the dorsal mesoderm are in blue. Here, 144 cases were included in the neural ridge group, 97 cases in the paraxial mesoderm group and 28 cases in the dorsal mesoderm group (Table 1). See the illustration in the link .
The pathological diagnosis has revealed a MEMB Méningioma of WHO in 243 tumors (90.3%), including 135 of meningothelial type, 49 transitional type and 49 of fibrous type. WHO grade II grade II tumors were detected in 26 cases (9.7 %), while no cases presented OMS grade III tumors. The proportion of fibrous meningiomas was relatively higher in the St-Med and the posterior base of the skull. WHO grade II meningiomas were more frequent in the St-Ant/LAT, St-Med, lateral and posterior regions, and meningothelial meningiomes were more frequent at the base of the skull, in particular in the “central” and “anterior” regions (Fig. 1D-F). One of the reasons for the small number of cases of grade II of the WHO here may be that our cohort has a high proportion of meningiomas from the base of the skull. Indeed, 171 of the 269 tumors (63.6 %) were located at the base of the skull.
With regard to the association between the pathological diagnosis and the embryological origins of the meninges, the proportion of meningothelial meningomes was significantly higher in patients whose lesions came from paraxial mesoderm rather than from the neural crest ( p = 5.5 × 10 –6 ) and the dorsal mesoderm ( p = 2.9 × 10 - 1g, h). However, the proportion of fibrous meningiomas was significantly higher in patients whose lesions came from the neural ridge rather than from the paraxial mesoderm (p = 0.01) (additional figure 1A). The proportion of MENINGIOMS of Grade II of the WHO was higher in patients whose lesions came from the neural ridge rather than from the paraxial mesoderm ( p = 1.4 × 10 –4 ) (additional figure 1b).
Genetic mutations and embryological origins of the meninges
The mutations detected in the 269 cases were located in AKT1 in 29 cases, KLF4 in 16 cases, SMO in one case, POLR2A in 17 cases, with NF2 and loss 22q in 87 cases, and NF2 only in 19 cases and loss only 22q in 53 cases (fig. 2). Representative cases and the results of the SANGER sequencing of each mutation are illustrated in the additional figure 2. These mutations were mutually exclusive and a single tumor presented NF2 and AKT1 . The remaining 48 cases were defined as "not detected", which implies that none of these changes have been detected (fig. 2). See the illustration in the link .
The tumors of almost all the patients carrying one of these four mutations were present along the base of the skull, with the exception of a patient carrying a mutation of KLF4 where the tumor was located in the St-Post/Lat region. SMO mutation had an earlier location; On the other hand, many tumors with KLF or POLR2A had a central location. In addition, many tumors with a mutation of AKT1 had an anterior and central location (fig. 3a-c). See the illustration in the link.
With regard to the association between genetic alterations and the embryological origins of the meninges, the 3D figure shows the number of patients carrying each genetic mutation in each region classified embryologically. Figure 3rd shows the number of patients carrying each genetic mutation at the base of the skull or at the supra -tentoriel level. In particular, the mutations of AKT1, KLF4, SMO or POLR2A were significantly more frequent in the paraxial mesodermal mesodermomas than in those of neural crest origin ( p = 1.7 × 10 –10 ) and dorsal mesodermic ( p = 3.0 × 10 –4 )) (fig. 3F). The mutations of AKT1, KLF4, SMO or POLR2A were significantly more frequent in the meningiomas of the lesions of the skull base than in those of the supra -tentory lesions ( p = 8.3 × 10 –11 ) (fig. 3G). With regard to patients with NF2 and/or a 22Q loss, these mutations were more frequent in the neural peak meningiomas only in those of paraxial mesodermal origin ( p = 3.9 × 10 –12 ) and more frequent in those of the neural crest only in those of dorsal mesodermal origin ( p = 5.0 × 10 -
Genetic mutations and pathological diagnosis
The number of patients with each mutation as a function of pathological diagnosis is indicated in a bar graph in Figure 4A. The mutation of AKT1, KLF4, SMO or POLR2A was significantly more frequent in the MENINGIOMS of Grade I of WHO than in the MENINGIOMS of Grade II of the WHO ( p = 0.01) (fig. 4b), and one of these four mutations was more frequently associated with maningothelial types than with other pathological types. ( p = 1.6 × 10 –5 ) (fig. 4c).
Exceptional, a patient had psammatic meningiomal with a Polr2A (fig. 4 additional), and another patient had an angiomatous meningioma with a KLF4 , while another patient still presented an atypical meningioma with an AKT1 . On the other hand, the 49 patients with fibrous meningomes and the 25 patients with MS grade II meningiomas did not present these four mutations, with the exception of a single patient. Forty-four of the 49 patients (89.8 %) with a fibrous type and 22 of the 25 patients (88.0 %) with MS grade II meningiom of WHO had a mutation of NF2 or a loss of 22q. NF2 mutations or loss 22q were significantly more frequent in fibrous meningiomas than in other pathological types ( p = 1.3 × 10 –7 ) (additional figure 5). See the illustration in the link.
Figure 5 sums up the anatomogenetic characteristics of each type of pathology.
Effects on meningioma recurrence rates
In this study, tumor locations classified by embryology were not prognostic factors , both with the log-trip ( p = 0.86) (Figure 6a) with a proportional Risk model of COX (Table 2). However, Kaplan-Meier curves comparing tumor recurrence between patients with different mutations and those who do not carry that the presence of a mutation can potentially play a predictive role (fig. 6b-e). Patients with POLR2A experienced a tumor recurrence with a high rate of 29.4 % (Table 1). This group had a significant difference on the log-trip test ( p = 0.05) (fig. 6D). In addition, we have analyzed the factors associated with tumor recurrence through a proportional COX risk model (Table 2).
The multivariate analysis was carried out using the factors whose value P was ≤ 0.20 during the univariate analysis. In the multivariate model, the WHO grade II ( p = 1.2 × 10 –4 , Hazard Ratio [HR] 4.99, 95 % confidence interval [CI] 2,20-11.3), the Simpson grade 1-3 ( p = 1.9 × 10 –6 0.11-0.39 ) and ( P = 1.7 × 10-2, HR 4.08, 95 % CI 1.28-13.0) were associated with tumor recurrence (Table 2). See the illustration and table in the link .
Five of the 17 patients with a POLR2A experienced a tumor recurrence. The five patients underwent a partial resection of the tumor during initial surgery because the tumor was located at the central skull base. POLR2A mutation served as a determinant of tumor recurrence independently of the Simpson grade 1-3. The duration of the follow -up of patients with the POLR2A was not very different from that of patients with other mutations. In addition, all patients with the POLR2A have been followed in our establishment. We examined the effect of the POLR2A on the tumors of grade I of the base of the skull according to the WHO and found that the patients carrying the POLR2A had a much more unfavorable prognosis ( p = 8.9 × 10 –3 ) (additional figure 6).
In addition, we have analyzed the factors associated with tumor recurrence through a proportional risk model of COX in this group (additional table 1). The multivariate analysis was carried out using the factors whose value P was ≤ 0.20 during the univariate analysis. In the multivariate model, the grade of Simpsons 1-3 ( p = 1.5 × 10 –3 , HR 0.25, 95 % CI 0.11-0.59), MIB-1 Li ≥ 3 ( p Polr2A mutation ( p = 0.04, HR 2.80, CI 95 % 1.16-9.53) were significantly associated with tumor recurrence. Consequently, the POLR2A mutation can be a potentially useful predictor of tumor recurrence in the grade I meningiomas of the base of the skull.
Discussion
This study exhaustively illustrates the anatomopathological association between pilot changes in meningiomas. Associations between anatomical locations, pathological diagnosis and pilot mutations were consistent with those reported above (12,16,19). However, this study reveals new results concerning associations between the embryological origins of the meninges to different anatomical locations, genetic history and pathological diagnoses. In addition, this study indicates that the mutation of POLR2A can serve as a potential marker for poor prognosis meningiomas.
This study defined the locations of the origins of tumors on the basis of existing knowledge on the embryological origin of the leptumeninc. The man-sighted convexes come from the skeleton-genesis layer which is immediately adjacent to them (20). In addition, Calvaria develops from the embryonic mesenchym of the head surrounding the brain, like the meninges; Consequently, its progenitors are probably included in the primary mening (21), which suggests a similar origin of the meninges and bones. Among mammals, the skull vault is built from embryogenic tissue of the neural crest and mesoderm (22,23). The coronal suture separates the frontal bone from the neural ridge of the parietal bone from the paraxial mesoderm (22.25). Consequently, the previous region of meningeal convexity should come from the neural crest and the posterior region of the paraxial mesoderm.
Falx Cerebri and cerebellar Tentorium are derived from the neural crest (20,22). The prechordial plaque differs in the neural crest and forms the cerebellar Tentorium which is adjacent to it (28). The neural crest forms the anterior region of the FALX. After the formation of the rear region of the FALX, the two regions interact.
Regarding the meninges of the skull base, McBratney-Owen et al. have reported that in the rat, the anterior cranial base is derived from the neural ridge, the posterior cranial base is derived from the mesoderm and the sphenoid bone is largely derived from the neural crest (24). However, the line of demarcation of these embryological contributions is different depending on the species studied (23). Overall, these studies indicate that the central base of the skull is derived from the paraxial mesoderm and that the posterior base of the skull comes from the dorsal mesoderm. The lateral region, including the sphenoid wing, is derived from the neural crest and the anterior base of the skull has no net border; However, a closer transitional area between the paraxial mesoderm and the neural crest is formed (23,24).
We evaluated the association between the location of tumors and pathological diagnoses by defining locations according to the embryological origin of the meninges. The tumors located in the original regions of the neural crest were associated with fibrous and grade II of the more frequent WHO. On the other hand, tumors located in the original regions of the paraxial mesoderm were associated with more frequent meningothelial meningomes. It was difficult to assess the meningiomas from the dorsal mesoderm due to the small cohort of patients here present; However, the trends were similar to those of the neural crest area. The association between the location of the tumor and histopathology could be based on embryonic dural development. Additional studies are necessary to prove this hypothesis.
This study showed the association between genetic alterations and tumor locations in accordance with previous relations (8,12,15,29). From an embryological point of view, we found that the meningiomas bearing mutations of AKT1, SMO, KLF4 or POLR2A were significantly associated with a paraxial mesodermic origin. However, meningiomas with NF2 or 22q loss were significantly associated with an origin of the neural crest and the dorsal mesoderm.
Previous studies have indicated that sensitivity to the loss of loss of function of NF2 differs between the meninges derived from the mesoderm and those derived from the neural crest in transgenic mice (30). Recently, Boetto et al. (26) reported that the selective sensitivity of the arachnoid from the skull base to the activation of the SMO initiated meningothelial meningiom in transgenic mice. These results can explain the differences in genetic status and pathology according to the location of the tumor. However, other biological studies on humans are necessary.
This study indicates associations between driver's mutations and histological results , which complies with previous reports (12.15). The proportion of meningothelial meningiomas housing mutations in AKT1 , KLF4 , SMO or POLR2A was significantly high. The fibrous and grade II tumors of the WHO mainly presented an NF2 or a 22q loss.
This study, as well as previous studies, clearly suggests that among the MEM Grade I meningiomas, the genetic background of the fibrous type differs from that of meningothelial and transitional (12,29) types. Previous studies have reported that in a transgenic mouse, meningothelial meningiomes came from the cells of the Arachnoid barrier and that fibrous meningiomas came from cells of the Dural Bordure (26,30). Apparently, these cells differ in their sensitivity to specific genetic mutations, depending on the location of the tumor (26,30,31). These results further corroborate the current association between pathological diagnoses and mutations.
This study shows that POLR2A mutation is a potentially appropriate marker for bad prognosis meningiomas, especially among the meningiomas of the base of grade I of WHO . Polr2A mutation was most often observed in the central region, which comes from the paraxial mesoderm. Polr2A is located at 17p13.1 and code for the Polymérase II RNA, which plays a fundamental role in eukaryotic organizations. POLR2A mutation in the meningiomas is currently unknown (32). A polymerase RNA inhibitor, alpha-amanitine, would remove the colorectal tumors bearing the POLR2A (33). POLR2A mutation . The clinical and biological characteristics of meningiomas carrying the POLR2A deserve to be specified.
One of the limits of our study is its retrospective and monocentric conception . Another limit would be that we have analyzed a limited number of genetic mutations. Mutations in the genes analyzed here are frequent; However, other mutations, including those in Traf7, HTERT, SMARCB1, SUFU and PIK3CA , also occur in meningiomas (15,34,35,36,37).
In addition, tumorigesis in meningiomas is associated not only with these pilot genetic mutations but also with overall gene expression profiles and methylation status (38). This study analyzed the genes with specific mutations by SANGER sequencing and a 22Q loss by microsatellite analysis. We believe that these genes can be easily analyzed in the clinical context. To completely elucidate the association between the tumorigesis of meningiomas and the embryological origin of the meninges, a complete genetic analysis, including that of the profiles of global expression and the status of methylation, is necessary.
Conclusion
This study shows that meningiomas, according to the embryological origin of their dural attachment, have differences in pathological diagnosis and genetic anomalies . In addition, this study is the first to show that the mutation of the POLR2A is a potential indicator of increased tumor recurrence . The evaluation of the embryological origin of the meninges can provide new information on the pathomechanism of meningiomas. Future molecular biology studies on the embryology of meninges are necessary.
Materials and methods
All methods have been carried out in accordance with the directives and regulations in force.
Patient population
This study was approved by the Institutional Review Council of the University of Tokyo (Approval number G10028), and the informed consent was obtained from all subjects. We have retrospectively analyzed the data of 499 patients who underwent meningiomas resection at the University of Tokyo hospital between January 2000 and June 2017. We excluded 153 patients for whom frozen fresh specimens or tumor DNA have not been obtained. When the patient has undergone several surgical interventions, data from the first intervention only were used. Seventy patients who have undergone an earlier tumor resection in another hospital were excluded. In addition, 2 patients with NF2, 2 patients who have undergone radiotherapy before the operation and 5 patients with multiple meningiomas were excluded from the study. Finally, the study included 269 patients.
Data collection
We evaluated the following parameters: sex, age, location of origin (attachment to the dura-mother), pathological diagnosis, extent of resection (grade of Simpsons), the need for additional treatment (surgery or/and radiosurgery), and the tumor's recidivism time by examining clinical and surgical files. The location was initially defined in accordance with the existing surgical classification based on the anatomical location of the dural attachment of the tumor, in order to precisely extract the data from these files. Thus, we classified the supra -tentory locations on convexity, the FALX and the parasagittal areas in three types: supra -tentory-medial (St-Med), Supra -tentolle-Latéral (St-Ant/LAT) and Supra -tentolle-Postéro-Latéral (St-Post/LAT). The limit between the “anterior” and “posterior” convexities was the coronal suture. In addition, the lesions of the skull base have been classified into four locations: anterior, central, posterior and lateral. The “anterior” lesions included the anterior cranial pit, the olfactory groove and the Sphenoidal Planum. The "central" lesions included the anterior clinoid apophysis, the posterior clinoid apophysis, the salt tuber, the meal cave, the cavernous sinus, the clival, the petroclival-anterior in the internal auditory meat (May), and the ponto-cerebellar angle (APC) -Anterier in May. “Lateral” lesions included the sphenoid wing and tentorial ties, extending into the average cranial pit, and all lesions of the average pit. The “posterior” lesions included the Magnum foramen, the APC posterior to AIM, the jugular foramen, the cerebellar convexity, and the tentoriel extending to the posterior pit (fig. 1). We classified the cases, which occupied wider areas, depending on the area of the largest attachment.
We have defined the places of origin of tumors on the basis of existing knowledge on the embryological origin of the leptumeninc (20,21,22,24,27). We have generated a diagram of normal development of the meninges according to their origin (additional figure 7). In addition, we have defined the embryological origins of the anatomical locations of the meninges as follows: origin of the neural ridge, including "lateral", "St-Med", "St-Ant/lat" and "Tentorium cerebellable"; PARAXIAL MÉSODERMIC Origin, including "Anterior“, ”Central” and ”St-Post/LAT”; dorsal mesodermal, including the "posterior" group.
The patients were followed by magnetic resonance imaging with contrast (MRI) to 2 days, 6 months and 1 year after surgery. If no tumor recurrence was observed, follow-up was continued regularly each year by MRI. For MRI, in any case, we made a central review. The precise locations of the origin of the tumor were defined thanks to the preoperative MRI images by inter-observer agreement between the neuro-radiologist and two neurosurgeons blind from clinical or genetic data. In addition, we have defined tumor recurrence by inter-observer agreement between the neuro-radiologist and two blind neurosurgeons to clinical or genetic data, on the detection of the apparent enlargement of residual tumors on MRI.
We have carried out a central examination of all pathological diagnoses for cases in accordance with the 2016 WHO classifications of the tumors of the central nervous system, including cases diagnosed on the basis of the WHO 2000 or 2007 classifications of the tumors of the central nervous system. Transitional meningioma has been defined on the basis of the 2016 WHO classifications of the tumors of the central nervous system such as a MENINGIOME of Grade I of the WHO characterized by the coexistence of meningothelial cells and fibrous architectural patterns. The MIB-1 Li was determined using the highest LI values in the areas of their maximum density, identified by a visual analysis.
DNA extraction and SANGER sequencing
The tumor DNA was extracted from freshly frozen tumors, using the minikit Qiamp DNA (QIIANGEN; Venlo, Netherlands) in accordance with the manufacturer's instructions, and the quality of DNA was evaluated using a spectrophotometer. We sequenced the hot changes in each gene, with the exception of NF2. Mutations in AKT1 (C.49G> A [P.GLU17LYS]), KLF4 (C.1228A> C [P.LYS409GLN]), SMO (C.1234C> T [P.LEU412PHE] and C.1604G> T [P.TRP535LEU]), and POLR2A (C.1207 C> [P.GLN403LYS] or C.1310-1315 DEL ACCTTC [P.LEU438_HIS439DEL]) were analyzed by sequencing SANGER Direct in all cases. The primers were designed using Primer3. As the NF2 does not have changes in mutation, we have done a SANGER Direct sequencing for all exons, using the primers generated from the Exon primer. For the PCR, 50 ng DNA and KOD FX NEO were used. The PCR was carried out with 20 µl of reaction mixtures and the following reaction cycles: initial denaturation at 94 ° C for 2 min, followed by 32 cycles with denaturation at 98 ° C for 10 s, reception at 58-60 ° C for 30 s, and extension to 68 ° C for 30 s, then final extension to 68 ° C for 7 min. The sequences were determined using an ABI 3130XL genetic analyzer (Applied Biosystems).
Microsatellite analysis
We carried out a microsatellite analysis to detect the 22Q loss. This analysis aimed to compare germinal and tumor DNA, using both blood and tumor samples. In our study, blood samples were obtained from 241 of the 269 patients. We used the following five polymorphic markers, NF2 , selected in the genome database: D22S268, D22S1163, D22S929, D22S280 and D2282 . The sensible primer was marked with a fluorescent dye and the PCR was carried out for 25 to 30 cycles at 58-60 ° C for hybridization, using the thermocycler Gene AMP 9700 (PE Biosystems; Framingham, Massachusetts, United States). PCR products were separated by capillary electrophoresis with the Genetic Analyzer 310, and the analysis was carried out using the Gene Scan program (PE Biosystems) (39).
Statistical analysis
The Chi square test was used to determine the association between the location of the tumor and the pathological diagnosis and between the location of the tumor and the genetic mutational status. For multiple comparisons, Bonferroni's correction was applied. Survival without progression has been defined as the delay between surgery and recurrence or final follow -up. The cases without recurrence were censored during the final follow -up. Kaplan-Meier's survival curves have been traced and the differences in progress without progression between the groups were compared using the log-trip test. We have evaluated the effect of sex, age, grade of Simpson, Mib-1 Li, pathological diagnosis, embryonic location of the tumor and mutational status by univariate analyzes with a proportional risk model of COX. Then, a multivariate analysis was carried out using the parameters whose value P was <0.2 during univariate analysis. All statistical analyzes were carried out with JMP Pro Version 11 (SAS Institute, Inc .; Cary, Caryoline du Nord, USA). A value p <0.05 was considered to be statistically significant. We excluded the SMO mutation from the evaluation factor because there was only one case with a SMO .
Data availability
Data is available on reasonable request. The authors confirm that the data supporting the results of this study will be shared at the request of any qualified investigator.
Thanks
We thank Dr. Kostadin Karagiozov for his support and help the rereading of English. This study benefited from the financial support of the subsidy for scientific research (B) (n ° 17:04301 for NS) of the Japanese company for the promotion of science, of the subsidy for scientific research (C) (n ° 19K09499 for HN) of the Japanese society for the promotion of science. Subsidy for scientific research (C) (n ° 19K09473 in SM) of the Japanese company for the promotion of science and research subsidy of the scientific foundation Takeda (at SM).
Authors information
Affiliation
- Department of Neurosurgery, Faculty of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-Ku, Tokyo, Japan
Atsushi Okano, Satoru Miyawaki, Hiroki Hongo, Shogo Dofuku, Yu Teranishi, Masahiro Shin, Hirofumi Nakatomi & Nobuhito Saito
- Department of Molecular Neurology, Higher School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-Ku, Tokyo, Japan
Jun Mitsui
- Departments of Neur-Endovascular Surgery, Kaneda Medical Center, 929 Higashi-Cho, Kamogawa, Chiba, Japan
Michihiro Tanaka
Contributions
Study Design: AO, SM, HN, NS Acquisition of Data: AO, HH, SD, YT, MS Analysis of Data: AO, MS, JM, Mt Drafting of Manuscript: AO, MS, HN, NS All Authors Have Read and Approved the Final Manuscript.
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