In another study, using a dextran sodium sulfate–induced colitis mouse model, ROS deficient Ncf1-mutant mice developed well-differentiated adenocarcinomas, while only high-grade dysplasia without malignant invasion was observed in ROS-proficient mice with Ncf1 wild type, suggesting that ROS deficiency may cause CRC in response to environmental risk factors [49]. The gene discussed is NCF1; the disease is colitis.