Transferrin is a glycoprotein that plays a crucial role in iron transport in the bloodstream. It binds ferric ions (Fe³⁺), forming a stable complex that is transported to cells through transferrin receptors (CD71) on the cell membrane. By maintaining cellular iron balance, transferrin helps protect against apoptosis, especially during iron deficiency. Transferrin levels and receptor expression serves as a key biomarkers for evaluating iron status, diagnosing anemia, and assessing cancer prognosis.