MFN1 and breast cancer: In hepatocytes, increased mitochondrial fission caused by low expression of PGC-1α promoted EMT.84 Similarly, loss of GCN5L1 facilitates ROS generation through reinforcing FAO, activating ERK and Drp1, which then initiates mitochondrial rupture, ultimately causing hepatocellular carcinoma (HCC) EMT and metastasis.89 Metastatic breast cancer cells have been found to exhibit a higher concentration of fragmented mitochondria, along with increased levels of Drp1 and fewer MFN1 molecules compared to nonmetastatic breast carcinoma cells.