Temporal and regional expression changes and co-staining patterns of metabolic and stemness-related markers during glioblastoma progression.

Glioblastomas (GBMs) are characterized by high heterogeneity, involving diverse cell types, including those with stem-like features contributing to GBM's malignancy. Moreover, metabolic alterations promote growth and therapeutic resistance of GBM. Depending on the metabolic state, antimetabolic treatments could be an effective strategy. Against this background, we investigated temporal and regional expression changes and co-staining patterns of selected metabolic markers [pyruvate kinase muscle isozyme 1/2 (PKM1/2), glucose transporter 1 (GLUT1), monocarboxylate transporter 1/4 (MCT1/4)] in a rodent model and patient-derived samples of GBM. To understand the cellular sources of marker expression, we also examined the connection of metabolic markers to markers related to stemness [Nestin, Krüppel-like factor 4 (KLF4)] in a regional and temporal context. Rat tumour biopsies revealed a temporally increasing expression of GLUT1, higher expression of MCT1/4, Nestin and KLF4, and lower expression of PKM1 compared to the contralateral hemisphere. Patient-derived tumours showed a higher expression of PKM2 and Nestin in the tumour centre vs. edge. Whereas rare co-staining of GLUT1/Nestin was found in tumour biopsies, PKM1/2 and MCT1/4 showed a more distinct co-staining with Nestin in rats and humans. KLF4 was mainly co-stained with GLUT1, MCT1 and PKM1/2 in rat and human tumours. All metabolic markers yielded individual co-staining patterns among themselves. Co-staining mainly occurred later in tumour progression and was more pronounced in tumour centres. Also, positive correlations were found amongst markers that showed co-staining. Our results highlight a link between metabolic alterations and stemness in GBM progression, with complex distinctions depending on studied markers, time points and regions.

IDH1 mutation is associated with improved resection rates, progression-free survival and overall survival in patients with anaplastic astrocytomas.

PURPOSE: The introduction of molecular markers in to the diagnosis of gliomas has changed the therapeutic approach to this tumors. The aim of this study was to examine the impact of surgery on anaplastic astrocytomas (AA), which has not previously been fully elucidated. METHODS: This was a retrospective study involving a total of 143 patients who underwent surgery for primary AA in our department between 1995 and 2020. RESULTS: Total tumor resection was achieved more often in patients with IDH-mutant tumors (41.09%) than in patients with IDH-wildtype tumors (30.76%). The median PFS was 1876 days for patients with IDH1 mutations and 238 days for patients with IDH-wildtype tumors. The 1-, 3-, 5- and 10-year PFS were longer in patients with total tumor resection and IDH-mutant AA (86.2%, 69%, 65.5% and 44.8%, respectively) than in patients with subtotal tumor resection and IDH-mutant AA (83.3%, 55.6%, 41.7% and 25%, respectively) and even longer compared to all IDH-wildtype tumors. The median OS was 2472 days for patients with IDH1 mutations and 434 days for patients with IDH-wildtype tumors. The 3-, 5- and 10-year OS times were longer in patients with total tumor resection and IDH-mutant AA (89.2%, 85.2% and 72.6%, respectively) than in patients with subtotal tumor resection and IDH-mutant AA (85.9%, 73.7% and 52.6%, respectively) and were even longer compared to all IDH-wildtype tumors. CONCLUSION: Total tumor resection is more common with IDH-mutant AA than with IDH-wildtype tumors. Patients with IDH-mutant AA had significantly better PFS and OS after total tumor resection than after subtotal tumor resection and biopsy.

Risks and neurological benefits of meningioma surgery in elderly patients compared to young patients.

INTRODUCTION: While surgery is the primary treatment choice for intracranial meningiomas in young patients, surgery in elderly patients, especially those with pre-existing comorbidities, has been the subject of repeated discussion. This study investigated the postoperative risks and neurological benefits of meningioma surgery in elderly patients compared to young patients. METHODS: In total, 768 patients were included and divided into two main groups: group I (age: ≤ 64 years; 484 young patients) and group II (age: ≥ 65 years; 284 elderly patients). Group II was subdivided into: IIa (age: 65-69 years), IIb (age: 70-79 years); and IIc (age: ≥ 80 years). RESULTS: The total tumor resection rate was higher in the elderly cohort than in the young cohort (84.5 and 76.2%, respectively). 154 young patients (31.8%) and 132 elderly patients (46.5%) developed postoperative morbidities, with the three most common being bleeding (12.9%), cranial nerve disorder (10%) and CSF fistula (8.1%). Postoperative bleeding, palsy, speech disorder, pneumonia and renal insufficiency were dependent on age (r = 0.123, p = 0.001; r = 0.089, p = 0.014; r = 0.100, p = 0.006; r = 0.098, p = 0.007 and r = 0.084, p = 0.020) and presented more often in elderly patients. 6 young and 15 elderly patients died during the 17.4-year observation period. Most patients showed a significant improvement in postoperative KPS (p < 0.001), except those over 80 years old (p = 0.753). The KPS at the last follow-up was significantly improved in all patients (p < 0.001). CONCLUSION: Meningioma surgery is associated with a higher rate of postoperative complications in elderly patients than in young patients. Most elderly patients, similar to young patients, show a significant improvement in neurological status postoperatively.

Intratumoral Distribution of Lactate and the Monocarboxylate Transporters 1 and 4 in Human Glioblastoma Multiforme and Their Relationships to Tumor Progression-Associated Markers.

(1) Background: Metabolic reprogramming has been postulated to be one of the hallmarks of cancer, thus representing a promising therapeutic target also in glioblastoma multiforme (GBM). Hypoxic tumor cells produce lactate, and monocarboxylate transporters (MCTs) play an important role in its distribution; (2) Methods: We examined the distribution of lactate by multi voxel magnetic resonance spectroscopic imaging and ELISA in glioblastoma multiforme (GBM) patients. In addition, we investigated the expression and cellular localization of MCT1, MCT4, and of several markers connected to tumor progression by quantitative PCR and immunofluorescence double-staining in human GBM ex vivo tissues; (3) Results: The highest lactate concentration was found at the center of the vital parts of the tumor. Three main GBM groups could be distinguished according to their regional gene expression differences of the investigated genes. MCT1 and MCT4 were found on cells undergoing epithelial to mesenchymal transition and on tumor stem-like cells. GBM cells revealing an expression of cellular dormancy markers, showed positive staining for MCT4; (4) Conclusion: Our findings indicate the existence of individual differences in the regional distribution of MCT1 and MCT4 and suggest that both transporters have distinct connections to GBM progression processes, which could contribute to the drug resistance of MCT-inhibitors.

Differential Diagnosis in Hypophysitis: First Report on a Spindle Cell Rhabdomyosarcoma of the Pituitary Gland.

Pituitary gland metastases are very rare. Most patients with pituitary gland metastases are asymptomatic; therefore, most cases of this disease are diagnosed during autopsies. Moreover, the four most common primary tumors that metastasize to the pituitary gland are breast, lung, thyroid, and renal carcinomas. We present a very rare case of pituitary metastasis of spindle cell rhabdomyosarcoma (RMS). Our patient presented with headache, visual disorder, panhypopituitarism, and diabetes insipidus. Due to tumor expansion, resection was not possible, so diagnosis was confirmed by biopsy, and chemotherapy and irradiation were administered. Our patient showed widespread spindle cell RMS, which harbors a mutation of myogenic differentiation 1 (MYOD1) and is associated with a poor prognosis. Even high-risk patients can show a remission after chemotherapy and irradiation. In the cases with indistinct lesions in the sella region, pituitary metastasis should always be considered.

Insights into Gene Regulation under Temozolomide-Promoted Cellular Dormancy and Its Connection to Stemness in Human Glioblastoma.

The aggressive features of glioblastoma (GBM) are associated with dormancy. Our previous transcriptome analysis revealed that several genes were regulated during temozolomide (TMZ)-promoted dormancy in GBM. Focusing on genes involved in cancer progression, Chemokine (C-C motif) Receptor-Like (CCRL)1, Schlafen (SLFN)13, Sloan-Kettering Institute (SKI), Cdk5 and Abl Enzyme Substrate (Cables)1, and Dachsous Cadherin-Related (DCHS)1 were selected for further validation. All showed clear expression and individual regulatory patterns under TMZ-promoted dormancy in human GBM cell lines, patient-derived primary cultures, glioma stem-like cells (GSCs), and human GBM ex vivo samples. All genes exhibited complex co-staining patterns with different stemness markers and with each other, as examined by immunofluorescence staining and underscored by correlation analyses. Neurosphere formation assays revealed higher numbers of spheres during TMZ treatment, and gene set enrichment analysis of transcriptome data revealed significant regulation of several GO terms, including stemness-associated ones, indicating an association between stemness and dormancy with the involvement of SKI. Consistently, inhibition of SKI during TMZ treatment resulted in higher cytotoxicity, proliferation inhibition, and lower neurosphere formation capacity compared to TMZ alone. Overall, our study suggests the involvement of CCRL1, SLFN13, SKI, Cables1, and DCHS1 in TMZ-promoted dormancy and demonstrates their link to stemness, with SKI being particularly important.

Impact of peritumoral brain edema on pre- and postoperative clinical conditions and on long-term outcomes in patients with intracranial meningiomas.

BACKGROUND: Peritumoral brain edema (PTBE) is a common complication related to intracranial meningiomas. In several studies, researchers have investigated the pathogenesis of PTBE, and the factors involved in its development in patients with intracranial meningiomas have been reported. However, very little is known about the clinical effect of PTBE on patients with intracranial meningiomas; therefore, a systematic examination of this matter is necessary. METHODS: In this study, we performed a systematic examination of 696 patients with primary intracranial meningiomas to assess the effect of preoperative PTBE on preoperative symptoms, neurological deficits and postoperative complications, and long-term outcomes with a follow-up period of 16.8 years. We performed a univariate analysis and multiple regression for specific outcomes and adjusted for other relevant clinical factors. RESULTS: A total of 627 (90.1%) patients were symptomatic preoperatively. One hundred eighty-eight (90.8%) patients with small to moderate PTBE and 125 (98.4%) patients with severe PTBE presented with symptoms significantly more often than the 314 (86.7%) patients without PTBE (p < 0.001, univariate analysis). Cognitive deficits, palsy and seizure were significantly more present, preoperatively, in patients with PTBE than in patients without PTBE (p < 0.001, univariate analysis). Two hundred fifty-five (36.6%) patients experienced surgical and systemic complications postoperatively. The complication rate was significantly higher in patients with PTBE; 41.5% for patients with small to moderate PTBE and 52.8% for patients with severe PTBE, compared to 28.2% of patients without PTBE (p < 0.001, univariate analysis). Furthermore, pre- and postoperative KPS scores were significantly lower in patients with PTBE (p < 0.001). Patients with PTBE required additional medical support significantly more often (p < 0.001) and had a significantly longer hospital stay (p < 0.001). The mortality rate was higher in patients with PTBE immediately after surgery and in the follow-up period; however, the difference was not significant. The neurological condition of all patients improved in the follow-up and did not show significant differences between patients with and without preoperative PTBE (p = 0.6361). Multiple logistic regression analyses revealed a significant association between PTBE and the presence of preoperative cognitive deficits, the incidences of seizure and postoperative complications, and low pre- and postoperative KPS scores. CONCLUSIONS: Preoperative PTBE significantly increased the incidences of specific preoperative symptoms, neurological deficits and postoperative complications in patients with intracranial meningiomas. After surgery, patients with preoperative PTBE required medical support significantly more often than patients without PTBE. However, all patients had favorable outcomes after surgery.

Surgical approach for convexity meningiomas: An analysis of the preoperative clinical signs, radiological features and surgical outcomes of these tumors.

BACKGROUND: Convexity meningiomas (CM) can be successfully treated with neurosurgery. However, clinical complications due to CM have been reported. Moreover, systematic investigations of CM with respect to all relevant clinical factors are currently lacking. METHODS: We performed a systematic investigation in 210 patients with supratentorial CM considering all relevant clinical and radiological factors, with a follow-up time of 19.5 years. RESULTS: Among 812 patients with intracranial meningiomas treated in our department (2003-2020), 28.2 % of intracranial meningiomas were located over the supratentorial convexity, and the patients had a median age of 62 years (95 % CI:59-64). The median follow-up was 30.4 months (95 % CI:21.6-37.1). Tumor-related symptoms were observed in 88.1 % of patients. The most common preoperative symptom was headache (28.1 %), followed by seizure (19.5 %). Symptomatic patients had significantly higher tumor volumes than asymptomatic patients (p = 0.0003; 24.5 cm3 and 6.98 cm3, respectively). Complete tumor resection was achieved in 92.9 % of patients. The most common postoperative complication was bleeding (7.1 %) in the approach area. Of all bleedings, only three were intracerebral hemorrhages and did not require surgical intervention. The second most common complication was postoperative seizure (4.7 %). The multiple logistic regression analyses showed that tumor volume (OR:1.007; 95 % CI:1.001-1.013; p = 0.02) and brain infiltration by the tumor (OR:1.961; 95 % CI:1.028-3.741; p = 0.04) had a significant impact on postoperative complications. The postoperative and final KPS scores significantly improved (p < 0.001). The tumor recurrence rate was 6.2 %, with a median time of 38 months. No surgery-related deaths occurred. CONCLUSION: A large tumor volume and brain infiltration by the tumor were significant factors for postoperative complications. The clinical conditions significantly improved postoperatively and further during the follow-up period.

Measurements of Functional Network Connectivity Using Resting State Arterial Spin Labeling During Neurosurgery.

In neurosurgery, an exact delineation of functional areas is of great interest to spare important regions to ensure the best possible outcome for the patient (i.e., maximum removal while maintaining the highest possible quality of life). Preoperative imaging is routinely performed, including the visualization of not only structural but also functional information. During surgery, however, brain shift can occur, leading to an offset between the previously defined and the real position. Real-time imaging during the procedure is therefore desired to obtain this information while performing surgery. In this study 15 patients suffering from glioblastoma multiforme were included. These patients underwent structural and perfusion imaging using arterial spin labeling during the procedure. The latter has been used for gathering information about tumor residual perfusion. However, special postprocessing of this data allows for additional mapping of resting state networks and is intended to be used to gather deeper insights to aid the surgeon in planning the procedure. The data of each patient could be successfully postprocessed and used to map different resting state networks alongside the default mode network. On the basis of this study, it is feasible to use the information obtained from perfusion imaging to visualize not only vascular signal but also functional activation of resting state networks without acquiring any additional data besides the already available information. This may help guide the neurosurgeon in real time to adjust the surgical plan.

To treat or not to treat? A retrospective multicenter assessment of survival in patients with IDH-mutant low-grade glioma based on adjuvant treatment.

OBJECTIVE: The level of evidence for adjuvant treatment of diffuse WHO grade II glioma (low-grade glioma, LGG) is low. In so-called "high-risk" patients most centers currently apply an early aggressive adjuvant treatment after surgery. The aim of this assessment was to compare progression-free survival (PFS) and overall survival (OS) in patients receiving radiation therapy (RT) alone, chemotherapy (CT) alone, or a combined/consecutive RT+CT, with patients receiving no primary adjuvant treatment after surgery. METHODS: Based on a retrospective multicenter cohort of 288 patients (≥ 18 years old) with diffuse WHO grade II gliomas, a subgroup analysis of patients with a confirmed isocitrate dehydrogenase (IDH) mutation was performed. The influence of primary adjuvant treatment after surgery on PFS and OS was assessed using Kaplan-Meier estimates and multivariate Cox regression models, including age (≥ 40 years), complete tumor resection (CTR), recurrent surgery, and astrocytoma versus oligodendroglioma. RESULTS: One hundred forty-four patients matched the inclusion criteria. Forty patients (27.8%) received adjuvant treatment. The median follow-up duration was 6 years (95% confidence interval 4.8-6.3 years). The median overall PFS was 3.9 years and OS 16.1 years. PFS and OS were significantly longer without adjuvant treatment (p = 0.003). A significant difference in favor of no adjuvant therapy was observed even in high-risk patients (age ≥ 40 years or residual tumor, 3.9 vs 3.1 years, p = 0.025). In the multivariate model (controlled for age, CTR, oligodendroglial diagnosis, and recurrent surgery), patients who received no adjuvant therapy showed a significantly positive influence on PFS (p = 0.030) and OS (p = 0.009) compared to any other adjuvant treatment regimen. This effect was most pronounced if RT+CT was applied (p = 0.004, hazard ratio [HR] 2.7 for PFS, and p = 0.001, HR 20.2 for OS). CTR was independently associated with longer PFS (p = 0.019). Age ≥ 40 years, histopathological diagnosis, and recurrence did not achieve statistical significance. CONCLUSIONS: In this series of IDH-mutated LGGs, adjuvant treatment with RT, CT with temozolomide (TMZ), or the combination of both showed no significant advantage in terms of PFS and OS. Even in high-risk patients, the authors observed a similar significantly negative impact of adjuvant treatment on PFS and OS. These results underscore the importance of a CTR in LGG. Whether patients ≥ 40 years old should receive adjuvant treatment despite a CTR should be a matter of debate. A potential tumor dedifferentiation by administration of early TMZ, RT, or RT+CT in IDH-mutated LGG should be considered. However, these data are limited by the retrospective study design and the potentially heterogeneous indication for adjuvant treatment.

A comparison of arterial spin labeling and dynamic susceptibility perfusion imaging for resection control in glioblastoma surgery.

Resection control using magnetic resonance imaging during neurosurgical interventions increases confidence regarding the extent of tumor removal already during the procedure. In addition to morphological imaging, functional information such as perfusion might become an important marker of the presence and extent of residual tumor mass. The aim of this study was to implement arterial spin labeling (ASL) perfusion imaging as a noninvasive alternative to dynamic susceptibility contrast (DSC) perfusion imaging in patients suffering from intra-axial tumors for resection control already during surgery. The study included 15 patients suffering from glioblastoma multiforme in whom perfusion imaging using DSC and ASL was performed before, during, and after surgery. The data obtained from intraoperative scanning were analyzed by two readers blinded to any clinical information, and the presence of residual tumor mass was evaluated using a ranking scale. Similarity of results was analyzed using the intraclass correlation coefficient and Pearson's correlation coefficient. The results show that intraoperative ASL is as reliable as DSC when performing intraoperative perfusion imaging. According to the results of this study, intraoperative imaging using ASL represents an attractive alternative to contrast agent-based perfusion imaging.

Intraoperative resection control using arterial spin labeling - Proof of concept, reproducibility of data and initial results.

OBJECTIVES: Intraoperative magnetic resonance imaging is a unique tool for visualizing structures during resection and/or for updating any kind of neuronavigation that might be hampered as a result of brain shift during surgery. Advanced MRI techniques such as perfusion-weighted imaging have already proven to be important in the initial diagnosis preoperatively, but can also help to differentiate between tumor and surgically induced changes intraoperatively. Commonly used methods to visualize brain perfusion include contrast agent administration and are therefore somewhat limited. One method that uses blood as an internal contrast medium is arterial spin labeling (ASL), which might represent an attractive alternative. MATERIALS AND METHODS: Ten healthy volunteers were examined using three different scanners and coils within 1 h (3T Achieva MRI using 32-channel head coil, 1.5T Achieva MRI using a 6-channel head coil, 1.5 Intera Scanner using 2 surface coils, Philips, Best, The Netherlands) and quantitative CBF values were calculated and compared between the different setups. Additionally, in eight patients with glioblastoma multiforme, ASL was used pre-, intra-, and postoperatively to define tumor tissue and the extent of resection in comparison to structural imaging. RESULTS: A high correlation (r = 0.91-0.96) was found between MRI scanners and coils used. ASL was as reliable as conventional MR imaging if complete resection was already achieved, but additionally provided valuable information regarding residual tumor tissue in one patient. CONCLUSIONS: Intraoperative arterial spin-labeling is a feasible, reproducible, and reliable tool to map CBF in brain tumors and seems to give beneficial information compared to conventional intraoperative MR imaging in partial resection.

Extensive growth of an anaplastic meningioma.

We present the case of a 30-year-old male patient with an almost complete destruction of the calvarial bone through an anaplastic meningioma diagnosed in line with dizziness. Neuroimaging revealed an extensive growing, contrast enhancing lesion expanding at the supra- and infratentorial convexity, infiltrating and destroying large parts of the skull, and infiltrating the skin. Due to progressive ataxia and dysarthria with proven tumor growth in the posterior fossa in the continuing course, parts of the tumor were resected. A surgical procedure with the aim of complete tumor resection in a curative manner was not possible. Six months after the first operation, due to a new tumor progression, most extensive tumor resection was performed. Due to the aggressive and destructive growth with a high rate of recurrence and tendency of metastases, anaplastic meningiomas can be termed as malignant tumors. The extrinsic growth masks the tumor until they reach a size, which makes these tumors almost unresectable. In the best case scenarios, the five-year survival is about 50%. With the presented case, we would like to show the aggressive behavior of anaplastic meningiomas in a very illustrative way. Chemotherapy, radiotherapy, and surgery reach their limits in this tumor entity.