In this study, we found that treatment with XN4 greatly increases the expression of Nox4 and Nox5 before increasing ROS production in CML cells, which indicates that XN4 may induce ROS generation, at least partially, by increasing Nox4 and Nox5 expression. Here, NOX5 is linked to chronic myelogenous leukemia, BCR-ABL1 positive.