We have created early-onset transgenic (Tg) models by exploiting the synergistic effects of familial Alzheimer's disease mutations on amyloid ␤-peptide (A␤) biogenesis. TgCRND8 mice encode a double mutant form of amyloid precursor protein 695 (KM670/671NL؉V717F) under the control of the PrP gene promoter. Thioflavine S-positive A␤ amyloid deposits are present at 3 months, with dense-cored plaques and neuritic pathology evident from 5 months of age. TgCRND8 mice exhibit 3,200 -4,600 pmol of A␤42 per g brain at age 6 months, with an excess of A␤42 over A␤40. High level production of the pathogenic A␤42 form of A␤ peptide was associated with an early impairment in TgCRND8 mice in acquisition and learning reversal in the reference memory version of the Morris water maze, present by 3 months of age. Notably, learning impairment in young mice was offset by immunization against A␤42

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Highlights d Hypoxic microenvironment is essential for propagation and growth of PFA ependymoma d Hypoxia controls metabolic intermediates that maintain an H3K27 hypomethylated genome d Inhibition or potentiation of histone lysine methylation diminishes PFA survival d Gliogenic lineage of developing fetal hindbrain mirrors PFA metabolic alterations

Medulloblastoma (MB) comprises a group of heterogeneous paediatric embryonal neoplasms of the hindbrain with strong links to early development of the hindbrain [1][2][3][4] . Mutations that activate Sonic hedgehog signalling lead to Sonic hedgehog MB in the upper rhombic lip (RL) granule cell lineage [5][6][7][8] . By contrast, mutations that activate WNT signalling lead to WNT MB in the lower RL 9,10 . However, little is known about the more commonly occurring group 4 (G4) MB, which is thought to arise in the unipolar brush cell lineage 3,4 . Here we demonstrate that somatic mutations that cause G4 MB converge on the core binding factor alpha (CBFA) complex and mutually exclusive alterations that affect CBFA2T2, CBFA2T3, PRDM6, UTX and OTX2. CBFA2T2 is expressed early in the progenitor cells of the cerebellar RL subventricular zone in Homo sapiens, and G4 MB transcriptionally resembles these progenitors but are stalled in developmental