The fusion process is mainly mediated by mitofusins 1 and 2 (MFN1, MFN2) on OMM and optic atrophy 1 (OPA1) on the inner mitochondrial membrane (IMM).[38] Depending on the tissue type of tumors, CSC stemness and self‐renewal can be enhanced by both mitochondrial fusion and fission.[39] However, it remains unclear whether the imbalance of mitochondrial dynamics is involved in the early onset of breast cancer. Here, MFN1 is linked to breast cancer.