Activation or inhibition of Forkhead box O (FoxO) through ROS-induced posttranslational modifications. An increase in intracellular ROS induces the activation of the kinases JNK and Akt and inhibits the deacetylase SIRT1 and Wnt/β-catenin signaling. The dephosphorylation and acetylation status of FoxO can lead to the induction of a specific subset of genes that regulates cellular detoxification. FoxO = Forkhead box O transcription factor, ROS = reactive oxygen species, FRE = FoxO response element, SOD = superoxide dismutase, GADD45 = growth arrest and DNA damage 45, OPG = osteoprotegerin, TCF/LEF = T-cell-specific transcription factor/lymphoid enhancing factor, Axin = axis inhibition, APC = adenomatous polyposis coli.