Cytotoxic T Cells and their Activation Status are Independent Prognostic Markers in Meningiomas.

PURPOSE: Clinically aggressive meningiomas (MGMs) are rare but treatment-resistant tumors in need for more effective therapies. Because tumor-infiltrating T lymphocytes (TILs) are essential for successful immunotherapy, we assessed TIL numbers and their activation status in primary (p-) and recurrent (r-) meningiomas and their impact on survival. EXPERIMENTAL DESIGN: Presence of TILs was analyzed in 202 clinically well-annotated cases (n = 123 pMGMs and n = 79 rMGMs) focusing on higher-grade meningiomas [n = 97 World Health Organization (WHO) °II, n = 62 WHO°III]. TILs were quantified by a semiautomated analysis on whole-tissue sections stained by multicolor immunofluorescence for CD3, CD8, FOXP3, and programmed cell death protein 1 (PD-1). RESULTS: Median T-cell infiltration accounted for 0.59% TILs per total cell count. Although there were no significant WHO°-dependent changes regarding helper (CD3+CD8-FOXP3-) and cytotoxic (CD3+CD8+FOXP3-) TILs in pMGMs, higher number of cytotoxic TILs were associated with an improved progression-free survival (PFS) independent of prognostic confounders. rMGMs were characterized by lower numbers of TILs in general, helper, and cytotoxic TILs. The additional analysis of their activation status revealed that a proportion of PD-1+CD8+ TILs within the TIL population was significantly decreased with higher WHO grade and in rMGMs. Furthermore, lower proportions of PD-1+CD8+ TILs were associated with inferior PFS in multivariate analyses, arguing for PD-1 as activation rather than exhaustion marker. CONCLUSIONS: We identified higher numbers of CD3+CD8+FOXP3- TILs and proportions of PD-1-expressing CD3+CD8+FOXP3- TILs as novel biomarkers for better survival. These findings might facilitate the selection of patients who may benefit from immunotherapy and argue in favor of an intervention in primary rather than recurrent tumors.

Identification of KIF11 As a Novel Target in Meningioma.

Kinesins play an important role in many physiological functions including intracellular vesicle transport and mitosis. The emerging role of kinesins in different cancers led us to investigate the expression and functional role of kinesins in meningioma. Therefore, we re-analyzed our previous microarray dataset of benign, atypical, and anaplastic meningiomas (n = 62) and got evidence for differential expression of five kinesins (KIFC1, KIF4A, KIF11, KIF14 and KIF20A). Further validation in an extended study sample (n = 208) revealed a significant upregulation of these genes in WHO°I to °III meningiomas (WHO°I n = 61, WHO°II n = 88, and WHO°III n = 59), which was most pronounced in clinically more aggressive tumors of the same WHO grade. Immunohistochemical staining confirmed a WHO grade-associated upregulated protein expression in meningioma tissues. Furthermore, high mRNA expression levels of KIFC1, KIF11, KIF14 and KIF20A were associated with shorter progression-free survival. On a functional level, knockdown of kinesins in Ben-Men-1 cells and in the newly established anaplastic meningioma cell line NCH93 resulted in a significantly inhibited tumor cell proliferation upon siRNA-mediated downregulation of KIF11 in both cell lines by up to 95% and 71%, respectively. Taken together, in this study we were able to identify the prognostic and functional role of several kinesin family members of which KIF11 exhibits the most promising properties as a novel prognostic marker and therapeutic target, which may offer new treatment options for aggressive meningiomas.

Anaplastic astrocytoma with piloid features, a novel molecular class of IDH wildtype glioma with recurrent MAPK pathway, CDKN2A/B and ATRX alterations.

Tumors with histological features of pilocytic astrocytoma (PA), but with increased mitotic activity and additional high-grade features (particularly microvascular proliferation and palisading necrosis) have often been designated anaplastic pilocytic astrocytomas. The status of these tumors as a separate entity has not yet been conclusively demonstrated and molecular features have only been partially characterized. We performed DNA methylation profiling of 102 histologically defined anaplastic pilocytic astrocytomas. T-distributed stochastic neighbor-embedding (t-SNE) and hierarchical clustering analysis of these 102 cases against 158 reference cases from 12 glioma reference classes revealed that a subset of 83 of these tumors share a common DNA methylation profile that is distinct from the reference classes. These 83 tumors were thus denominated DNA methylation class anaplastic astrocytoma with piloid features (MC AAP). The 19 remaining tumors were distributed amongst the reference classes, with additional testing confirming the molecular diagnosis in most cases. Median age of patients with MC AAP was 41.5 years. The most frequent localization was the posterior fossa (74%). Deletions of CDKN2A/B (66/83, 80%), MAPK pathway gene alterations (49/65, 75%, most frequently affecting NF1, followed by BRAF and FGFR1) and mutations of ATRX or loss of ATRX expression (33/74, 45%) were the most common molecular alterations. All tumors were IDH1/2 wildtype. The MGMT promoter was methylated in 38/83 tumors (45%). Outcome analysis confirmed an unfavorable clinical course in comparison to PA, but better than IDH wildtype glioblastoma. In conclusion, we show that a subset of histologically defined anaplastic pilocytic astrocytomas forms a separate DNA methylation cluster, harbors recurrent alterations in MAPK pathway genes in combination with alterations of CDKN2A/B and ATRX, affects patients who are on average older than those diagnosed with PA and has an intermediate clinical outcome.

3D rotational fluoroscopy for intraoperative clip control in patients with intracranial aneurysms--assessment of feasibility and image quality.

BACKGROUND: Mobile 3D fluoroscopes have become increasingly available in neurosurgical operating rooms. In this series, the image quality and value of intraoperative 3D fluoroscopy with intravenous contrast agent for the evaluation of aneurysm occlusion and vessel patency after clip placement was assessed in patients who underwent surgery for intracranial aneurysms. MATERIALS AND METHODS: Twelve patients were included in this retrospective analysis. Prior to surgery, a 360° rotational fluoroscopy scan was performed without contrast agent followed by another scan with 50 ml of intravenous iodine contrast agent. The image files of both scans were transferred to an Apple PowerMac® workstation, subtracted and reconstructed using OsiriX® free software. The procedure was repeated after clip placement. Both image sets were compared for assessment of aneurysm occlusion and vessel patency. RESULTS: Image acquisition and contrast administration caused no adverse effects. Image quality was sufficient to follow the patency of the vessels distal to the clip. Metal artifacts reduce the assessability of the immediate vicinity of the clip. Precise image subtraction and post-processing can reduce metal artifacts and make the clip-site assessable and depict larger neck-remnants. CONCLUSION: This technique quickly supplies images at adequate quality to evaluate distal vessel patency after aneurysm clipping. Significant aneurysm remnants may be depicted as well. As it does not require visual control of all vessels that are supposed to be evaluated intraoperatively, this technique may be complementary to other intraoperative tools like indocyanine green videoangiography and micro-Doppler, especially for the assessment of larger aneurysms. At the momentary state of this technology, it cannot replace postoperative conventional angiography. However, 3D fluoroscopy and image post-processing are young technologies. Further technical developments are likely to result in improved image quality.

Developmental potential of the murine embryonic stem cells transplanted into the healthy rat brain--novel insights into tumorigenesis.

Although engraftment of undifferentiated pluripotent embryonic stem cells (ESCs) into the injured central nervous system (CNS) may lead to targeted cell replacement of lost/damaged cells, sustained proliferative activity combined with uncontrolled differentiation of implanted cells presents a risk of tumor formation. As tumorigenic potential is thought to be associated with pluripotency of embryonic stem cells, pre-differentiation may circumvent this problem. Recently, it has been demonstrated that tumorigenesis occurs despite pre-differentiation if the neural precursor cells are implanted into the brain of a homologous animal (e.g., mouse to mouse). However, xenotransplantation (e.g., mouse to rat) without pre-differentiation, lead to the development of healthy neuronal cells, in absence of tumor formation, suggesting that tumor-suppressive effects of host tissue on engrafted ESCs may play a role in transplant tumorigenesis. We critically investigated tumorigenesis and possible mechanisms of anticipated tumor-suppressive effect under conditions analogous to previously published studies. Xenotransplantation of D-3 murine ESCs into uninjured adult rat brains lacking any preliminary inflammatory potential was found to lead to tumor formation in 5 out of 8 of animals within 2 weeks postimplantation. Tumor-suppressive effects, reflected by Erdo et. al could possibly be ascribed to immunomodulatory activity of macrophages scavenging the tumorigenic fraction of the implanted cells. The importance of number of engrafted cells, implantation site and immunosuppressive effects are discussed as possible variables determining tumorigenic outcome after ESC transplantation.