Fig. 2

Hematoxylin-eosin staining from a representative tumor area shows densely packed and poorly differentiated neoplastic cells with high nucleus:cytoplasmic ratio and high levels of mitotic activity (A and inset). Tumor cells displays immunoreactivity for Synaptophysin (B) and low to moderate expression of p53 (C). Subgroup-specific immunohistochemical markers show cytoplasmic, but no nuclear β-catenin expression (D) as well as diffuse positivity for Yap1 (E) and Gab1 (F). Overall, these findings are consistent with the diagnosis of SHH MB, p53-wt. The methylation profiling assigned the methylation MB subclass SHH-A (children and adult) according to the v11b4 Brain Tumor Classifier and MB SHH-activated, subtype 4 according to the newest version (v12.5). The copy number profile (G) calculated from DNA methylation array data of the tumor sample showing gain of chromosome 3 and a focal loss in chromosome 7 with no other relevant chromosomal aberration