SREBF1 and neoplasm: In advanced cancers, rapamycin-mediated inhibition of mTORC1 releases feedback loops that activate the mTOR complex 2 (mTORC2) and sustain tumor survival via AKT17, 18 and SREBP-1-dependent fatty acid synthesis.19 The activity of PA-generating enzymes, predicted to limit rapamycin inhibition,20 might also temper the rapamycin-triggered feedback loops responsible for resistance in advanced cancers.