Characteristics of PDOX models of primary and recurrent meningioma. (A) H&E-stained paraffin sections of whole mouse brains bearing the intracranial xenograft tumors derived from the primary grade II (K29P) and recurrent grade III (K29R) meningiomas. (B) MRI showing the growth of cranial-base xenografts (red circles) of K29P-PDOX and obstructive hydrocephalus. (C). Kaplan–Meier survival curves for K29P and K29R PDOX models (p = 0.0390, n = 8 out of 10 and 9 out of 9, respectively). (D). H&E staining of xenograft and human tumors in the K29P and K29R-PDOX models. Areas of necrosis are circled in red. (E). Representative images of IHC staining in matching patient tumor and PDOX models. MT: Mitochondria (human-specific). Ki-67: Cell proliferation. VWF: Von Willebrand factor (micro-vessels). VIM: Neurofilament vimentin. PDGFR1: EMA and platelet-derived growth factor receptor 1. Scale bars: (A,B) 500 mm, (D,E) 75 mm. Abbreviations: patient-derived orthotopic xenograft (PDOX); Hematoxylin and eosin (H&E); magnetic resonance imaging (MRI); immunohistochemistry (IHC); epithelial membrane antigen (EMA).