Emil J. Freireich (March 16, 1927 – February 1, 2021) was an American hematologist, oncologist, and cancer biologist. He was recognized as a pioneer in the treatment of cancer and use of chemotherapy and is often known as the father of modern leukemia therapy. Early life Freireich was born in Chicago on March 16, 1927. His Jewish parents, Mary (Klein) and David Freireich, immigrated to the United States from Hungary. He grew up in poverty during the Great Depression. His father died when he was two years old, and his mother worked in a factory to support Emil and his elder sister. After winning a science fair, a teacher recommended that he consider going to college. He attended the University of Illinois at Urbana–Champaign at the age of 16 with the help of donations from neighbors, and later from scholarships. He was medically excused from being drafted into World War II because of a broken leg. He earned his M.D. from the University of Illinois College of Medicine in 1949. After graduation from medical school, he did an internship at Cook County Hospital. However, he was fired due to a dispute with the administrators, after he attempted to treat a patient with heart failure who had been transferred to the hospital's "death room" and left for dead. As a result, he moved to Presbyterian Hospital of Chicago where he studied internal medicine under Howard Armstrong. He subsequently studied hematology under Joe Ross at Mass Memorial Hospital in Boston, and published a study on anemia during his time there. It was there that he also met his wife, Haroldine Cunningham, who worked as a nurse at the hospital. He moved to the National Institutes of Health in 1955 to avoid being drafted into the army as a physician by joining the Public Health Service. One decade later, he joined the University of Texas MD Anderson Cancer Center in Houston, together with Emil Frei, his friend and co-worker at the National Cancer Institute (NCI). They were tasked with creating a chemotherapy program. Combination chemotherapy In 1965, Freireich, Frei, and James F. Holland hypothesized that cancer could best be treated by combinations of drugs, each with a different mechanism of action. Cancer cells could conceivably mutate to become resistant to a single agent, but by using different drugs concurrently it would be more difficult for the tumor to develop resistance to the combination.