NQO1 (NAD(P)H Quinone Dehydrogenase 1): NQO1 is an enzyme that helps protect cells from oxidative stress by converting quinones into less reactive hydroquinones. This process reduces the formation of harmful reactive oxygen species and supports cellular redox balance. Variations in the NQO1 gene have been linked to cancer risk and increased sensitivity to certain toxins, emphasising its role in detoxification and cellular defence.