HIF1A and breast cancer: Also, the inhibition of FASN activity, which is up-regulated in hypoxic regions of breast cancer tumours via the activation of Akt and HIF-1α-induced sterol regulatory element binding protein-1, using cerulenin or PI3K inhibitor LY294002, has also been observed to reverse the resistance of breast cancer cells to cyclophosphamide under hypoxic conditions [265].