Immunohistochemistry of a posterior fossa group A ependymoma

Representative image of H3K27me3 immunohistochemical (IHC) staining of a posterior fossa group A ependymoma (PF-EPN-A). The only cells that stain positive for H3K27me3 are those of the tumor microenvironment, including endothelial cells, which serve as an internal positive control (circles). Tumor cells demonstrate an absence of H3K27me3 staining, characteristic of PF-EPN-A tumors.