To address whether genetic activation or disruption of Nrf2 affects the development of colorectal tumors, we generated Gstp−/−: ApcMin/+: Nrf2−/−: Keap1+/+ and Gstp−/−: ApcMin/+: Nrf2+/+: Keap1flox/flox mice by crossing Gstp−/−: ApcMin/+ mice with Nrf2−/− or Keap1flox/flox mice, respectively, all on the C57BL/6 genetic background. The gene discussed is KEAP1; the disease is colorectal neoplasm.