To gain insight into in vivo tumor evolution and progression, we examined if the histopathological features and, more importantly, the progression nature of the original patient tumor were replicated in the PDOX tumors during long-term serial subtransplantations in mouse brains, followed by the analysis of the underlying cellular and molecular (e.g. BRAF V600E mutation and CDKN2A deletion) changes in tumor cells and in the host normal brain cells that drove or accompanied the PDOX tumor progression to identify new therapeutic targets. Here, BRAF is linked to neoplasm.