APOE and neoplasm: To examine the spatial distribution of APOE, the tumor-containing brain was divided into three parts using QuPath software based on Hoechst and H&E staining: the tumor core, the tumor edge, defined as the area extending 200 μm from the tumor border, and the peritumoral normal tissue, defined as the region extending 200–400 μm from the tumor border (Fig. 1B).