ATRX Glioma Marker White Paper

The protein encoded by the ATRX gene belongs to a chromatin-remodeling pathway (H3.3-ATRX-DAXX) and is required for the incorporation of H3.3 in chromatin.

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Mutations in this gene are associated with various changes in the pattern of DNA methylation, chromosome congression during mitosis, segregation in meiosis, and telomere dysfunction^1.

These changes may provide a link between chromatin remodeling, DNA methylation, and gene expression in developmental processes [provided by RefSeq, Jul 2017]. Phenotypically, the mutations result in several characteristic developmental abnormalities such as mental retardation, facial dysmorphism, and alpha-thalassemia (ATRX) syndrome¹.

Figure 1: A. Immunohistochemical staining of human glioma tissue using HPA001906 shows strong nuclear im- immunoreactivity in cancer cells. B. Western blot analysis in A-549 cells transfected with control siRNA, target-specific siRNA probe #1 and #2, using Anti-ATRX antibody. The remaining relative intensity is presented. Loading control: Anti-GAPDH.

Figure 2: A. Immunohistochemical staining of human brain (high-grade glioma) using AMAb90784 shows strong nuclear immunoreactivity in cancer cells. B. Immunofluorescence staining in HeLa cell line with AMAb90784 shows clear nuclear (without nucleoli) staining in green. The microtubule probe is visualized in red. C. Western blot analysis in A-549 cells transfected with control siRNA, target-specific siRNA probe #1 and #2, using Anti-ATRX antibody. The remaining relative intensity is presented. Loading control: Anti-GAPDH.

ATRX, a marker for glioma

Around 2012, several research groups worldwide started to study the potential link between ATRX and glioma.

In this paper^1, the authors summarized the recent studies and the correlations made between different markers such as IDH1, p53, 1p/19q, and ATRX with different types of glioma.

Figure 3: Multiplexed IHC-IF staining of glioblastoma multiforme (A) and oligodendroglioma (B) shows ATRX (red) and IDH1 (green) immunoreactivity in tumor cells using Anti-ATRX antibody (A: HPA001906, B: AMAb90784) and Anti-IDH1 antibody (AMAb90578). Nuclei are counterstained with DAPI.

Figure 4: Multiplexed IHC-IF staining of glioblastoma multiforme (A), astrocytoma (B), and oligodendroglioma (C) shows ATRX (nuclear, red) and GFAP (cytoplasmic, green) immunoreactivity in tumor cells using Anti-ATRX antibody (AMAb90784) and Anti-GFAP antibody (AMAb91033). Nuclei are counterstained with DAPI.

The paper concluded that depending on mutations in IDH1, 1p/19q, and ATRX, gliomas could be classified into three groups:

Molecular Astrocytomas
Molecular Oligodendrogliomas
Molecular Glioblastomas

ATRX has become a routine marker for the classification of gliomas and is most often used in combination with various other markers such as IDH1^1-7, P53^2,3,4,7, PARP1³, GFAP⁶, KI-67^2, and EGFR².

The images below show examples of immunohistochemical stainings of select cases of glioblastomas, astrocytomas, and oligodendrogliomas using antibodies for ATRX, IDH1, and GFAP.