We found that inhibiting mitochondrial FAO through CAC (carnitine-acylcarnitine carrier; CACT, carnitine-acylcarnitine translocase; gene name SLC25A20) knockdown caused an accumulation of mid-chain and long-chain acyl-carnitines in pancreatic ductal adenocarcinoma (PDAC) cells, resulting in a substantial decrease in ATP production, which in turn inactivated mTOR signaling. The gene discussed is SLC25A20; the disease is pancreatic ductal adenocarcinoma.