PDCD4 and lung carcinoma: Interestingly, antioxidants such as CAT were able to inhibit chronic Cr(VI)-induced miR-21 elevation and PDCD4 suppression, demonstrating that ROS have a crucial role in the regulation of the miR-21/PDCD4 signaling in lung cancer, which the authors suggested to happen through IL-6/STAT3 [224].