Figure 1. OPA1 participates in different steps of tumorigenesis and metastatization. Tumor initiation: OPA1 is upregulated in a variety of cancer types, favoring proliferation, and protecting them from apoptosis. Exponential growth: endothelial OPA1 enhances tumor vascularization. By interacting with the mitochondrial calcium uptake machinery component MICU1, OPA1 limits Ca2+ accumulation in the cytosol, a negative regulator endothelial cells proliferation and migration. (3) Metastases dissemination: Endothelial OPA1 favors lymphatic vessels differentiation from venous blood vessels. (4) Chemoresistance: OPA1 overexpression in cancer cells curtails cristae remodeling, a key step for cytochrome c release and induction of cell death by targeted and conventional anti-cancer drugs.