Excess heme released due to tissue damage or disease exerts toxic effects on multiple organs. Free heme—that is, heme not bound to proteins—is toxic because it induces oxidative stress through the generation of reactive oxygen species (ROS). Under normal conditions, proteins such as haptoglobin and hemopexin neutralize free heme; however, these defenses can be easily overwhelmed during disease. Consequently, heme-induced injury in various pathological states may lead to renal, cardiac, and hepatic damage.


Additionally, an increased rate of heme consumption and metabolism fuels cancer growth and progression. As a critical component of the electron transport chain, heme is essential for mitochondrial energy production. Several cancer types have been shown to rely on enhanced heme metabolism, actively modulating heme pathways to meet their heightened energy demands.