2. E. Donnall Thomas (Physician)

E. Donnall Thomas was a pioneering physician who developed and refined bone marrow transplantation techniques to treat blood cancers like leukemia. His work involved replacing damaged or diseased bone marrow with healthy stem cells, enabling patients to recover their blood and immune systems. His groundbreaking efforts transformed cancer treatment and saved many lives, earning him the Nobel Prize in Physiology or Medicine in 1990. In essence, Thomas's contributions laid the foundation for modern stem cell therapy, offering new hope to patients with otherwise fatal blood diseases.