A Children’s Hospital of Philadelphia team reported a case of neuroepithelial tumor linked to rare adeno-associated virus (AAV) integration following intracisternal magna vector delivery for an inherited lysosomal disorder. The work was presented at ASGCT 2026 and published in the New England Journal of Medicine, with sequencing showing a vector fragment integrated into exon 5 of PLAG1 and PLAG1 expression elevated in the tumor.