POU5F1 and neoplasm: The number of tumor spheres, the percentages of CD44+ cells and CD133+ cells, and the expression of multiple stem cell core proteins (Sox2, Oct4, Nanog, and ALDH1A1) were all increased when the cells were treated with GM‐Exo but were markedly reduced in GM‐ExoS100A9KD‐treated CT‐26 cells (Figure4A–E).