HMOX1 and atherosclerosis: In addition, generation of ROS by arsenic increases the expression of atherosclerosis related genes such as heme oxygenase-1 (HO-1), monocyte chemo-attractant protein-1 (MCP-1), and interleukin-6 (IL-6) and thus its exposure promotes the attachment, penetration, and migration of monocytes in vascular smooth muscle cells [104].