APOE and neoplasm: Macrophage in this cluster had high expression of type I interferon signaling related genes (IFITM3, IFI27, MX1, IFI6, and ISG15) as well as gene features related to immunosuppressive phenotype (APOE, APOC1, S100A9, and GPNMB) (47, 64, 65), whereby participating in tumor immune regulation (66, 67).