4-Hydroperoxy cyclophosphamide is the active metabolite form of the prodrug Cyclophosphamide. 4-Hydroperoxy cyclophosphamide crosslinks DNA and induces T cell apoptosis independent of death receptor activation, but activates mitochondrial death pathways through production of reactive oxygen species (ROS). 4-Hydroperoxy cyclophosphamide has the potential for lymphomas and autoimmune disorders.