This picture is similar to that observed in the case of apoptosis, angiogenesis, or regulation of mitochondrial metabolism, where the effect of OPA1 is not phenocopied by the MFNs [23, 24, 39, 40], and these results are important in the context of the ongoing efforts to understand the role of mitochondrial morphology vs. that of each of these individual proteins with pleiotropic functions beyond the control of mitochondrial shape in breast cancer. This evidence concerns the gene OPA1 and breast cancer.