DLK2 and breast cancer: For instance, during the invasion and migration of breast cancer cells, the expression of delta-like non-canonical Notch ligand 2 (DLK2), a member of the epithelial growth factor (EGF) repeat superfamily protein, is regulated to enter the mitochondria and interact with the cox assembly factor 3 (COA3) to reduce its activity, thereby decreasing mitochondrial oxidative metabolism and increasing lactate release and glucose absorption, thus promoting the metabolic transition process from OXPHOS to glycolysis and realizing its metastasis [415].