The cell composition of the glioblastoma (GBM) microenvironment depends on the recruitment of myeloid cells from the blood, promoting tumor progression by inducing immunosuppression. This phenomenon hampers immunotherapies and investigating its complexity may help to tailor new treatments. Peripheral blood and tissue specimens from the central and marginal tumor areas were collected from 44 primary and 19 recurrent GBM patients. Myeloid and lymphoid cell subsets and the levels of immunosuppressive markers were defined by multiparametric flow cytometry. Multiplexed immunohistochemistry was used to confirm the differences in the immune infiltrate and to analyze the cell spatial distribution. Relapsing GBM showed an increased presence of blood-derived macrophages in both tumor areas and a higher frequency of infiltrating lymphocytes, with a high level of exhaustion markers. The expansion of some myeloid-derived suppressor cell (MDSC) subsets in the blood was found in both primary and recurrent GBM patients. A significant inverse correlation between infiltrating T cells and an MDSC subset was also found. In patients with recurrent GBM after standard first-line therapy, the immune-hostile tumor microenvironment and the levels of some MDSC subsets in the blood persisted. Analysis of the immune landscape in GBM relapses aids in the definition of more appropriate stratification and treatment.

Ependymomas are rare primary central nervous system tumors. They can form anywhere along the neuraxis, but in adults, these tumors predominantly occur in the spine and less frequently intracranially. Ependymal tumors represent a heterogenous group of gliomas, and the WHO 2016 classification is based essentially on a grading system, with ependymomas classified as grade I, II (classic), or III (anaplastic). In adults, surgery is the primary initial treatment, while radiotherapy is employed as an adjuvant treatment in some cases of grade II and in all cases of anaplastic ependymoma; chemotherapy is reserved for recurrent cases. In recent years, important and interesting advances in the molecular characterization of ependymomas have been made, allowing for the identification of nine molecular subgroups of ependymal tumors and moving toward subgroup-specific patients with improved risk stratification for treatment-decisions and future prospective trials. New targeted agents or immunotherapies for ependymoma patients are being explored for recurrent disease. This review summarizes recent molecular advances in the diagnosis and treatment of intracranial ependymomas including surgery, radiation therapy and systemic therapies.

Histopathological screening of excised tissue is the current “gold standard” in post-surgical oncological practice,¹ for clinical and molecular evaluation of critical parameters such as type, grading, and classification of tumors, e.g., in glioma and glioblastoma (GBM) resection. ^{2 – 4} Normal routine involves the dispatch of fresh surgical biopsies after resection to the histopathology laboratory: therefore, the samples are typically fixed for preservation, sectioned, stained—various staining techniques are used, with hematoxylin and eosin (H&E) staining being the most prominent— and then imaged with a microscope to determine their structural and molecular composition.³ However, modern histopathological analysis presents several limitations, the most severe one being the lengthy preparation of the samples that lead to long duration of the procedures to obtain the final results, which can vary from several days to even weeks after the surgery. Extemporaneous and intraoperative analyses can be much faster (minutes to hours), but the number of biopsy samples is limited due to operational logistics and costs of the procedures, and the breadth of information they can provide is very limited for diagnostic purposes.⁵ Furthermore, diagnosis and classification can be affected by variability in the subjective interpretation of the results by histopathologists, with the screening essentially lacking a more quantitative and objective way to systematically process the imaging outcomes.⁶ Overall, postoperative prognosis and planning would enormously benefit from a different approach to histopathology that could provide much faster and more reliable information on the tissue biopsies, ideally by having a screening in situ right after the surgery that could lead to quantitative results in a matter of minutes to hours.

OBJECTIVE: The onco-functional balance represents the primary goal in neuro-oncology. The increasing use of navigated transcranial magnetic stimulation (nTMS) allows the noninvasive characterization of cortical functional anatomy, and its reliability for motor and language mapping has previously been validated. Calculation and arithmetic processing has not been studied with nTMS so far. In this study, the authors present their preliminary data concerning nTMS calculation. METHODS: The authors designed a monocentric prospective study, adopting an internal protocol to use nTMS for preoperative planning, including arithmetic processing. When awake surgery was possible, according to the patients’ conditions, nTMS points were used to guide direct cortical stimulation (DCS), i.e., the gold standard for cortical mapping. Navigated TMS–based tractography was used for surgical planning. Statistical analyses on the nTMS and DCS points were performed. RESULTS: From February 2021 to October 2023, 61 procedures for nTMS calculation mapping were performed. The clinical evaluation, including pre- and postoperative evaluations (3 months after surgery), demonstrated a good clinical outcome with preservation of arithmetic function and recovery (92.8% of patients). Between the awake and asleep surgery groups, the postoperative clinical results were comparable at the 3-month follow-up, with > 90% of the patients achieving improved calculation function. The surgical strategy adopted was aimed at sparing nTMS positive points in asleep procedures, whereas nTMS and DCS positive points were not removed in awake procedures. Overall, 62% of the positive points for calculation functions were exposed by craniotomy and 85% were spared during surgery. None of the patients developed nTMS-related seizures. Diffusion tensor imaging fiber tracking based on nTMS positive points for calculation was used. The white matter fiber tracts involved in calculation functions were the arcuate fasciculus (56%) and frontal aslant tract (22%). When nTMS and DCS points were compared in awake surgery (n = 10 patients), a sensitivity of 31.71%, specificity of 85.76%, positive predictive value of 22.41%, negative predictive value of 90.64%, and accuracy of approximately 69% were achieved. CONCLUSIONS: Based on the authors’ preliminary data, nTMS can be an advantageous tool to study cognitive functions, aimed at minimizing neurological impairment. The postoperative clinical outcome for patients who underwent operation with nTMS was very good. Considering these results, nTMS has proved to be a feasible method to map cognitive areas including those for calculation functions. Further analyses are needed to validate these data. Finally, other cognitive functions (e.g., visuospatial) may be explored with nTMS.

SignificanceAccurate and timely characterization of brain tumors remains a major challenge in neurosurgery. Current intraoperative guidance relies on preoperative imaging modalities such as magnetic resonance imaging, positron emission tomography, or computed tomography, which are essential for surgical planning but become less reliable during surgery due to brain shift. Furthermore, postoperative tumor classification depends on histopathology, which requires weeks and can delay treatment decisions. No existing tool offers real-time, label-free, and spatially resolved biomolecular information to support both intraoperative guidance and early tissue assessment.AimWe developed HyperProbe1.1 (HP1.1), a hyperspectral imaging system designed to acquire comprehensive molecular and metabolic information from brain tissue without the need for contrast agents or staining.ApproachHP1.1 captures reflectance images across a broad range of narrow spectral bands, enabling spatial mapping of hemoglobin, cytochrome c oxidase, and oxygen saturation. In addition, ultraviolet-excited autofluorescence imaging provides information on metabolic cofactors - nicotinamide adenine dinucleotide and flavin adenine dinucleotide - relevant for tumor characterization. The system was validated using standardized phantoms and ex vivo glioma samples.ResultsHP1.1 demonstrated strong performance in detecting spectral features across phantoms and in distinguishing glioma tissues of different histological grades, enabling the generation of rapid and spatially resolved molecular contrast maps.ConclusionsBy providing label-free, high-content, and rapid biomolecular imaging, HP1.1 represents a powerful platform for noninvasive tissue assessment in controlled experimental settings and paves the way for future intraoperative applications.