Pathological significance of epidermal growth factor receptor expression and amplification in human gliomas

Artificial Intelligence Imaging for Predicting High-risk Molecular Markers of Gliomas

Gliomas, the most prevalent primary malignant tumors of the central nervous system, present significant challenges in diagnosis and prognosis. The fifth edition of the World Health Organization Classification of Tumors of the Central Nervous System (WHO CNS5) published in 2021, has emphasized the role of high-risk molecular markers in gliomas. These markers are crucial for enhancing glioma grading and influencing survival and prognosis. Noninvasive prediction of these high-risk molecular markers is vital. Genetic testing after biopsy, the current standard for determining molecular type, is invasive and time-consuming. Magnetic resonance imaging (MRI) offers a non-invasive alternative, providing structural and functional insights into gliomas. Advanced MRI methods can potentially reflect the pathological characteristics associated with glioma molecular markers; however, they struggle to fully represent gliomas' high heterogeneity. Artificial intelligence (AI) imaging, capable of processing vast medical image datasets, can extract critical molecular information. AI imaging thus emerges as a noninvasive and efficient method for identifying high-risk molecular markers in gliomas, a recent focus of research. This review presents a comprehensive analysis of AI imaging's role in predicting glioma high-risk molecular markers, highlighting challenges and future directions.

Epidermal Growth Factor Receptor: Key to Selective Intracellular Delivery

Epidermal growth factor receptor (EGFR) is an integral surface protein mediating cellular response to a number of growth factors. Its overexpression and increased activation due to mutations is one of the most common traits of many types of cancer. Development and clinical use of the agents, which block EGFR activation, became a prime example of the personalized targeted medicine. However, despite the obvious success in this area, cancer cure remains unattainable in most cases. Because of that, as well as the result of the search for possible ways to overcome the difficulties of treatment, a huge number of new treatment methods relying on the use of EGFR overexpression and its changes to destroy cancer cells. Modern data on the structure, functioning, and intracellular transport of EGFR, its natural ligands, as well as signaling cascades triggered by the EGFR activation, peculiarities of the EGFR expression and activation in oncological disorders, as well as applied therapeutic approaches aimed at blocking EGFR signaling pathway are summarized and analyzed in this review. Approaches to the targeted delivery of various chemotherapeutic agents, radionuclides, immunotoxins, photosensitizers, as well as the prospects for gene therapy aimed at cancer cells with EGFR overexpression are reviewed in detail. It should be noted that increasing attention is being paid nowadays to the development of multifunctional systems, either carrying several different active agents, or possessing several environment-dependent transport functions. Potentials of the systems based on receptor-mediated endocytosis of EGFR and their possible advantages and limitations are discussed.

Impact of H3.3 K27M Mutation on Prognosis and Survival of Grade IV Spinal Cord Glioma on the Basis of New 2016 World Health Organization Classification of the Central Nervous System

BACKGROUND

Spinal cord glioma grade IV is a rare, diffuse midline glioma. H3 K27M-mutant was classified in a different entity in the 2016 World Health Organization (WHO) classification recently. No reports about prognosis of spinal cord glioma grade IV are available yet.

OBJECTIVE

To analyze the prognostic factors for spinal cord glioma grade IV.

METHODS

Twenty-five patients with spinal cord glioma of grade IV who underwent surgery in a single institute were selected. All grade IV spinal cord glioma histologically confirmed as glioblastoma or "diffuse midline glioma with H3 K27M-mutant" by the 2016 WHO classification of the central nervous system were included. Basic demographics, treatment modalities, and pathological tumor molecular profiles were investigated for prognosis.

RESULTS

Mean age was 39.1 yr; male to female ratio was 18 : 7. Tumor was located in thoracic cord (53.3%), cervical cord (40%), and lumbar area (6.7%). Median overall survival was 37.1 mo; median disease-free survival was 18.5 mo. Treatment modality showed no statistical difference. Only K27M profile showed significant prognostic value, 20 patients (80%) showed K27M mutation positive, K27M mutation patients showed longer overall survival (40.07 mo) than K27M negative patients (11.63 mo, P < .0001), and disease-free survival (20.85 vs 8.72 mo, P = .0241).

CONCLUSION

This study is the first and largest report of the prognosis of primary spinal cord grade IV glioma using the new WHO classification. This study reported survival analysis and prognostic factors, and revealed that H3.3 K27M mutation is not a major poor prognostic factor. Further studies to explore K27M mutations needed for risk stratification and therapy optimization.

Expression of p53 & epidermal growth factor receptor in glioblastoma

Background & objectives:

Glioblastoma (GB) is the most frequent brain tumour, manifesting at any age, with a peak incidence between 45 and 75 years. Primary and secondary GBs constitute relatively distinct disease entities in evolution, in expression profiles and in therapeutic response. Histopathologically, primary and secondary GBs are indistinguishable. The aim of this investigation was to study the immunohistochemical (IHC) expression of p53 and epidermal growth factor receptor (EGFR) in GB with the objective of categorizing the morphological variants of GB into primary and secondary based on the presence of low-grade areas and knowing the variable expression of p53 and EGFR in primary and secondary GB.

Methods:

A total of 28 patients with GB were studied and categorized into primary and secondary based on the presence of low-grade areas, i.e. discernible astrocytic morphology, gemistocyte and oligodendroglia. Tumours with the presence of combination of the above features or any one of the above features were taken as secondary GB, whereas tumours with highly pleomorphic areas were considered as primary GB. IHC was done on the representative tissue blocks for p53 and EGFR.

Results:

Majority of the patients were in the fifth and sixth decades of life with a mean age of 46.96±13 yr with male preponderance (male:female 2.5:1). Mean age of presentation was 48.93±12 yr in primary and 44.69±15 yr in secondary GB. All cases of GB were classified into primary (53.57%) and secondary (46.43%) based on morphology. EGFR was more frequently expressed than p53. Based on IHC, 50 per cent of cases were classified into primary, three per cent into secondary and 47 per cent as unclassified.

Interpretation & conclusions:

Histopathological features, i.e. presence of low-grade areas, may play a role in classifying GB into primary and secondary. EGFR has a pivotal role in gliomagenesis. Combination of p53 and EGFR alone may not be sufficient to clarify GB into primary and secondary.

Prognostic significance of epidermal growth factor receptor expression in glioma patients

Purpose

There is a great controversy regarding the prognostic significance of epidermal growth factor receptor (EGFR) in glioma patients. The current meta-analysis was conducted to evaluate the effect of abnormal EGFR expression on overall survival in glioma patients.

Materials and methods

A comprehensive literature search of PubMed, EMBASE, Google Scholar, Web of Science, and Cochrane Library was conducted. The combined hazard ratio (HR) and its 95% confidence intervals (CIs) were used to evaluate the association between EGFR expression and survival in glioma.

Results

A total of 476 articles were screened, and 17 articles containing 1,458 patients were selected. The quality assessment of the included studies was performed by the Newcastle-Ottawa Scale. Overexpression of EGFR was found to be an indicator of poor prognosis in overall survival in glioma patients (HR =1.72, 95% CI 1.32-2.25, P=0.000, random effect) and glioblastoma multiforme patients (HR =1.57, 95% CI 1.15-2.14, P=0.004, random effect). Subgroup analysis was conducted to explore the source of high heterogeneity.

Conclusion

This meta-analysis indicated that high expression of EGFR may serve as a biomarker for poor prognosis in glioma patients.

Efficacy and safety results of ABT-414 in combination with radiation and temozolomide in newly diagnosed glioblastoma

BACKGROUND

The purpose of this study was to determine the maximum tolerated dose (MTD), recommended phase II dose (RPTD), safety, and pharmacokinetics of ABT-414 plus radiation and temozolomide in newly diagnosed glioblastoma. ABT-414 is a first-in-class, tumor-specific antibody-drug conjugate that preferentially targets tumors expressing overactive epidermal growth factor receptor (EGFR).

METHODS

In this multicenter phase I study, patients received 0.5-3.2 mg/kg ABT-414 every 2 weeks by intravenous infusion. EGFR alterations, O6-methylguanine-DNA methyltransferase (MGMT) promoter hypermethylation, and isocitrate dehydrogenase (IDH1) gene mutations were assessed in patient tumors. Distinct prognostic classes were assigned to patients based on a Molecular Classification Predictor model.

RESULTS

As of January 7, 2016, forty-five patients were enrolled to receive ABT-414 plus radiation and temozolomide. The most common treatment emergent adverse events were ocular: blurred vision, dry eye, keratitis, photophobia, and eye pain. Ocular toxicity at any grade occurred in 40 patients and at grades 3/4 in 12 patients. RPTD and MTD were set at 2 mg/kg and 2.4 mg/kg, respectively. Among 38 patients with pretreatment tumor tested centrally, 39% harbored EGFR amplification, of which 73% had EGFRvIII mutation. Among patients with available tumor tissue (n = 30), 30% showed MGMT promoter methylation and none had IDH1 mutations. ABT-414 demonstrated an approximately dose proportional pharmacokinetic profile. The median duration of progression-free survival was 6.1 months; median overall survival has not been reached.

CONCLUSION

ABT-414 plus chemoradiation demonstrated an acceptable safety and pharmacokinetic profile in newly diagnosed glioblastoma. Randomized studies are ongoing to determine efficacy in newly diagnosed (NCT02573324) and recurrent glioblastoma (NCT02343406).

Proximity ligation assay evaluates IDH1R132H presentation in gliomas

For a targeted cancer vaccine to be effective, the antigen of interest needs to be naturally processed and presented on MHC by the target cell or an antigen-presenting cell (APC) in the tumor stroma. The presence of these characteristics is often assumed based on animal models, evaluation of antigen-overexpressing APCs in vitro, or assays of material-consuming immune precipitation from fresh solid tissue. Here, we evaluated the use of an alternative approach that uses the proximity ligation assay (PLA) to identify the presentation of an MHC class II-restricted antigen in paraffin-embedded tissue sections from patients with brain tumors. This approach required a specific antibody directed against the epitope that was presented. We used an antibody that specifically binds an epitope of mutated isocitrate dehydrogenase type 1 (IDH1R132H), which is frequently expressed in gliomas and other types of tumors. In situ PLA showed that the IDH1R132H epitope colocalizes with MHC class II in IDH1R132H-mutated glioma tissue. Moreover, PLA demonstrated colocalization between the class II epitope-containing melanoma antigen New York esophageal 1 and MHC class II. Collectively, our data suggest that PLA may be a useful tool to acquire information on whether an antigen is presented in situ, and this technique has potential to guide clinical studies that use antigen-specific cancer immunotherapy.

Glioma spheroids obtained via ultrasonic aspiration are viable and express stem cell markers: a new tissue resource for glioma research

BACKGROUND

Ultrasonic aspirators allow safe, rapid, and accurate removal of brain tumors. However, the tissue fragments removed are used surprisingly little in research.

OBJECTIVE

To investigate whether such tissue fragments could be cultured as organotypic multicellular spheroids because access to biopsy tissue is often limited.

METHODS

Tissue fragments obtained by ultrasonic aspiration from 10 glioblastomas and tumor biopsy tissue from 7 of these tumors were cultured in serum-containing and serum-free medium. On culturing, the fragments formed spheroids, which were prepared for histology. Two glioblastoma cell lines from ultrasonic fragments and biopsy tissue were established as well.

RESULTS

Hematoxylin and eosin staining showed viable glioma spheroids obtained from both ultrasonic and biopsy tissue in both types of medium. Endothelial growth factor receptor and PTEN/chromosome 10 status was found to be preserved in most spheroids (7-8 of 10 tumors), together with the level of glial fibrillary acidic protein, von Willebrand factor, and Ki-67. The levels of stem cell markers CD133, Bmi-1, nestin, and Sox2 also were preserved. The ultrasonic spheroids had higher levels of glial fibrillary acidic protein and von Willebrand factor and lower levels of Bmi-1, nestin, Sox2, and Olig2 compared with conventional biopsy spheroids. For both types of spheroids, the stem cell medium seemed to favor expression of stem cell markers. The established cell lines were capable of both spheroid formation at clonal density and tumor formation in vivo.

CONCLUSION

Viable organotypic and proliferating spheroids were easily obtained from ultrasonic tissue fragments. The preservation of markers and the establishment of cell lines with tumor-initiating cell properties suggest ultrasonic spheroids as a new tissue resource for glioma research.

A novel EGFR isoform confers increased invasiveness to cancer cells

As a validated therapeutic target in several human cancers, the EGF receptor (EGFR) provides a focus to gain deeper insights into cancer pathophysiology. In this study, we report the identification of a naturally occurring and widely expressed EGFR isoform termed EGFRvA, which substitutes a Ser/Thr-rich peptide for part of the carboxyl-terminal regulatory domain of the receptor. Intriguingly, EGFRvA expression relates more closely to histopathologic grade and poor prognosis in patients with glioma. Ectopic expression of EGFRvA in cancer cells conferred a higher invasive capacity than EGFR in vitro and in vivo. Mechanistically, EGFRvA stimulated expression of STAT3, which upregulated heparin-binding EGF (HB-EGF). Reciprocally, HB-EGF stimulated phosphorylation of EGFRvA at Y845 along with STAT3, generating a positive feedback loop that may reinforce invasive function. The significance of EGFRvA expression was reinforced by findings that it is attenuated by miR-542-5p, a microRNA that is a known tumor suppressor. Taken together, our findings define this newfound EGFR isoform as a key theranostic molecule.