Together, these data suggested that the SiO2-induced NOX4 and ROS generation played a pivotal role in the EMT and fibrogenesis in lung epithelial cells during silicosis, which also implied an underlying mechanism by which interaction between the Wnt/β-catenin signaling and NOX4 of lung epithelial cells was implicated in the pathogenesis of silicosis lungs. This evidence concerns the gene NOX4 and silicosis.