Extracellular Histones Profiles of Pediatric H3K27-Altered Diffuse Midline Glioma.

in Molecular diagnosis & therapy by Diana Buzova, Lucia Lisa Petrilli, Jan Frohlich, Desislava K Tsoneva, Salvatore Daniele Bianco, Maria Rita Braghini, Anna Alisi, Angela Mastronuzzi, Jan Cerveny, Tommaso Mazza, Maria Vinci, Manlio Vinciguerra

TLDR

  • The study is looking for a way to diagnose a rare type of brain tumor called diffuse midline glioma, H3 K27-altered (DMG) in the blood of children. They found that there are certain proteins in the blood that are different in children with DMG/DIPG compared to healthy children. These proteins could be used to diagnose DMG/DIPG and monitor the treatment of the disease. The study also found that these proteins could be used to personalize treatment for DMG/DIPG. The study's method could be used to diagnose other types of brain tumors and other diseases. The study's findings could improve the speed and accuracy of diagnosis and lead to better treatment outcomes for children with DMG/DIPG.

Abstract

Diffuse midline glioma, H3 K27-altered (DMG) is a fatal tumour that arises in the midline structures of the brain. When located in the pons, it is more commonly referred to as diffuse intrinsic pontine glioma (DIPG). DMG/DIPG is usually diagnosed when children are < 10 years, and it has a median overall survival of < 12 months after diagnosis. Radiological imaging is still the gold standard for DIPG diagnosis while the use of biopsy procedures led to our knowledge on its biology, such as with the identification of the canonical histone H3K27M mutation. However, the need to improve survival encourages the development of non-invasive, fast and inexpensive assays on biofluids for optimizing molecular diagnoses in DMG/DIPG. Here, we propose a rapid, new, imaging and epigenetics-based approach to diagnose DMG/DIPG in the plasma of paediatric patients. A total of 20 healthy children (mean age: 10.5 years) and 24 children diagnosed with DMG/DIPG (mean age: 8.5 years) were recruited. Individual histones (H2A, H2B, H3, H4, macroH2A1.1 and macroH2A1.2), histone dimers and nucleosomes were assayed in biofluids by means of a new advanced flow cytometry ImageStream(X)-adapted method. We report a significant increase in circulating histone dimers and tetramers (macroH2A1.1/H2B versus control: p value < 0.0001; macroH2A1.2/H2B versus control: p value < 0.0001; H2A/H2B versus control: p value < 0.0001; H3/H4 versus control: p value = 0.008; H2A/H2B/H3/H4 versus control: p value < 0.0001) and a significant downregulation of individual histones (H2B versus control: p value < 0.0001; H3 versus control: p value < 0.0001; H4 versus control: p value < 0.0001). Moreover, histones were also detectable in the cerebrospinal fluid (CSF) of patients with DMG/DIPG and in the supernatant of SF8628, OPBG-DIPG002 and OPBG-DIPG004 DMG/DIPG cell lines, with patterns mostly similar to each other, but distinct compared to blood plasma. In summary, we identified circulating histone signatures able to detect the presence of DMG/DIPG in biofluids of children, using a rapid and non-invasive ImageStream(X)-based imaging technology, which may improve diagnosis and benefit the patients.

Overview

  • The study aims to develop a rapid, non-invasive, imaging and epigenetics-based approach to diagnose diffuse midline glioma, H3 K27-altered (DMG) in the plasma of paediatric patients. The study recruited 20 healthy children and 24 children diagnosed with DMG/DIPG. The researchers used a new advanced flow cytometry ImageStream(X)-adapted method to assay individual histones, histone dimers, and nucleosomes in biofluids. The primary objective of the study is to identify circulating histone signatures that can detect the presence of DMG/DIPG in biofluids of children.

Comparative Analysis & Findings

  • The study found a significant increase in circulating histone dimers and tetramers (macroH2A1.1/H2B versus control: p value < 0.0001; macroH2A1.2/H2B versus control: p value < 0.0001; H2A/H2B versus control: p value < 0.0001; H3/H4 versus control: p value = 0.008; H2A/H2B/H3/H4 versus control: p value < 0.0001) and a significant downregulation of individual histones (H2B versus control: p value < 0.0001; H3 versus control: p value < 0.0001; H4 versus control: p value < 0.0001) in the plasma of children with DMG/DIPG compared to healthy children. The study also found that histones were detectable in the cerebrospinal fluid (CSF) of patients with DMG/DIPG and in the supernatant of DMG/DIPG cell lines, with patterns mostly similar to each other, but distinct compared to blood plasma. These findings suggest that circulating histone signatures can be used to detect the presence of DMG/DIPG in biofluids of children.

Implications and Future Directions

  • The study's findings have significant implications for the diagnosis and treatment of DMG/DIPG. The non-invasive and rapid nature of the proposed approach could improve the speed and accuracy of diagnosis, leading to better treatment outcomes for patients. The study also identifies potential biomarkers for DMG/DIPG, which could be used for personalized treatment and monitoring. Future research could focus on validating the circulating histone signatures in larger cohorts of patients and developing a clinical assay for DMG/DIPG diagnosis. Additionally, the study's methodology could be adapted for use in other types of brain tumors and other biofluids.
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