Alternative definition : NCI-GLOSS: A process in which the liver uses one of two major enzyme pathways to change
a toxic substance, such as an anticancer drug, into a less toxic substance that is
easier for the body to excrete.;
NCIt note : Phase I detoxification pathways involve the oxidation of toxins, drugs or steroid
hormones by cytochrome P-450 system enzymes. (see Peace-Brewer, AL. DetoxiGenomic
Profile, Physicians Copy. Genova Diagnostics. GDX-4-179. GDG02 RMS 1427 Rev 1);