Radiological evaluation of ex novo high grade glioma: velocity of diametric expansion and acceleration time study

Quantitative evaluation of neuroradiological and morphometric alteration of inferior Fronto-Occipital Fascicle across different brain tumor histotype: an Italian multicentric study

BACKGROUND

Inferior Fronto-Occipital Fascicle (IFOF) is a multitasking connection bundle essential for communication and high level mentalization. The aim of the present study was to quantitatively assess its radiological-anatomical-morphometric modifications according to different brain tumor histotype.

METHODS

A retrospective multicentric Italian study was conducted. IFOF reconstructions were calculated for both hemispheres for each patient diagnosed with Glioblastoma (GBM), Low Grade Glioma (LGG), Brain Metastasis and Meningioma using Elements Fibertracking software (Brainlab AG). A 3D object of each fascicle was evaluated for volume, average fractional anisotropy (FA) and length. The cerebral healthy hemisphere was compared to the pathological contralateral in different tumor histotype.

RESULTS

1294 patients were evaluated. 156 met the inclusion criteria. We found a significant difference between healthy hemisphere and the contralateral for IFOF mean length and volume (p-value < 0.001). Considering GBM subgroup, Student's t-test confirmed the results. In LGG subgroup, there was significant difference between the 2 hemispheres for IFOF mean length, mean FA and volume (respectively p-value 0.011; p-value 0.021, p-value < 0.001). In patients affected by brain metastasis (18) Student's t-test showed a significant difference for FA and volume (p-value 0.003 and 0.02 respectively). No differences were found in patients affected by meningiomas.

CONCLUSIONS

The careful preoperative neuroradiological evaluation of the brain-tumor interface is indispensable to plan a tailored surgical strategy and perform a safe and effective surgical technique. It depends on the tumor histology and pattern of growth. GBM have a mixed component, with the solid enhancing nodule which accounts for IFOF displacement and the peritumoral area which accounts for an infiltrative/destructive effect on the fascicle. LGG determine a prevalent infiltrative pattern. Metastases determine an IFOF dislocation due to peritumoral oedema. Meningiomas do not impact on WM anatomy.

Metabolic delineation of IDH1 wild-type glioblastoma surgical anatomy: how to plan the tumor extent of resection

PURPOSE

Magnetic resonance imaging (MRI) is the current standard for preoperative planning of glioblastoma (GBM) surgery. However, recent data on the use of ¹¹ C-methionine positron emission tomography (¹¹[C]-MET PET) suggest its role in providing additional information beyond MRI. The purpose of this study is to establish if there is a correlation between anatomical and metabolic data.

METHODS

We retrieved all GBM cases treated from 2014 to January 2021. Preoperative MRI (Enhancing Nodule -EN-, FLAIR and Total Tumor Volume -TTV-), PET volumes and histological samples obtained from the different tumor regions were evaluated to analyze potential correlations between anatomical, metabolic and pathological data.

RESULTS

150 patients underwent surgery for GBM and 49 of these were also studied preoperatively with ¹¹[C]-MET PET; PET volume was evaluated in 47 patients. In 33 patients (70.21%) preoperative ¹¹[C]-MET PET volume > preoperative EN volume and in 11 (23.4%) preoperative ¹¹[C]-MET PET volume > preoperative TTV. We found a significant correlation between preoperative TTVs and PET volumes (p = 0.016) as well as between preoperative EN volumes and PET volumes (p = < 0.001). Histologically, 109 samples were evaluated. ENs samples exhibited the conventional GBM morphology while samples from the FLAIR regions showed white matter tissue, with focal to diffuse tumor cells infiltration and areas of reactive astrogliosis.

CONCLUSION

We submit that ¹¹[C]-MET PET volume generally overcome EN. The presence of neoplastic cells confirm these metabolic data. It should be considered in the surgical planning to achieve a Supra Total Resection (SupTR).

Anatomical distribution of cancer stem cells between enhancing nodule and FLAIR hyperintensity in supratentorial glioblastoma: time to recalibrate the surgical target?

It is ge nerally accepted that glioblastoma (GBM) arise from cancer stem cells (CSC); however, there is little evidence on their anatomical distribution. We investigated the expression and distribution of SOX-2-positive and CD133-positive CSCs both in the enhancing nodule (EN) of GBM and in the FLAIR hyperintensity zones on a surgical, histopathological series of 33 GBMs. The inclusion criterion was the intraoperative sampling of different tumor regions individualized, thanks to neuronavigation and positivity to intraoperative fluorescence with the use of 5-aminolevulinic acid (5-ALA). Thirty-three patients (20 males and 13 females with a mean age at diagnosis of 56 years) met the inclusion criterion. A total of 109 histological samples were evaluated, 52 for ENs and 57 for FLAIR hyperintensity zone. Considering the quantitative distribution of levels of intensity of staining (IS), ES (extent score), and immunoreactivity score (IRS), no difference was found between ENs and FLAIR regions for both the SOX-2 biomarker (respectively, IS p = 0.851, ES p = 0.561, IRS p = 1.000) and the CD133 biomarker (IS p = 0.653, ES p = 0.409, IRS p = 0.881). This evidence suggests to recalibrate the target of surgery for FLAIRECTOMY and 5-ALA could improve the possibility to achieve this goal.

Hypermethylation of the Promoter of miR-338-5p Mediates Aberrant Expression of ETS-1 and Is Correlated With Disease Severity Of Astrocytoma Patients

The pro-oncogene ETS-1 (E26 transformation-specific sequence 1) is a key regulator of the proliferation and invasion of cancer cells. The present work examined the correlation of the aberrant expression of ETS-1 with histological or clinical classification of astrocytoma: grade I (pilocytic astrocytoma), grade II (diffuse astrocytoma), grade III (anaplastic astrocytoma), and grade IV (glioblastoma multiforme). MicroRNA, miR-338-5p, was predicted by an online tool (miRDB) to potentially target the 3' untranslated region of ETS-1; this was confirmed by multi-assays, including western blot experiments or the point mutation of the targeting sites of miR-338-5p in ETS-1's 3'untralation region (3'UTR). The expression of miR-338-5p was negatively associated with that of ETS-1 in astrocytoma, and deficiency of miR-338-5p would mediate aberrant expression of ETS-1 in astrocytoma. Mechanistically, hypermethylation of miR-338-5p by DNA methyltransferase 1 (DNMT1) resulted in repression of miR-338-5p expression and the aberrant expression of ETS-1. Knockdown or deactivation of DNMT1 decreased the methylation rate of the miR-338-5p promoter, increased the expression of miR-338-5p, and repressed the expression of ETS-1 in astrocytoma cell lines U251 and U87. These results indicate that hypermethylation of the miR-338-5p promoter by DNMT1 mediates the aberrant expression of ETS-1 related to disease severity of patients with astrocytoma.