FIS1 and neoplasm: To ensure that the new stem cells remain their properties, mitochondria divide asymmetrically, and healthy mitochondria enter new stem cells.298 Overexpression of mitochondrial fission factor (MFF) boosts mitochondrial fission to enhance the stemness and tumor-initiating capacity of liver cancer-initiating cells.299 Similarly, in primitive acute myeloid leukemia cells, activating mitophagy needs the expression of mitochondrial fission 1 (FIS1).