CXCL5 and prostate cancer: Furthermore, treatment with the CXCR2 inhibitor SB225002 blocked HO-1 expression and upregulated endogenous ROS and H2O2-induced ROS levels in prostate cancer cells (Figure 3 and Figure 5), indicating that CXCL5 affects endogenous ROS and H2O2-induced ROS, and is dependent on HO-1 and CXCR2.