In 1928, George Papanicolaou discovered that vaginal cell smears (the Pap smear) revealed the presence of cervical cancer. Although his initial publication of the finding in 1928 went largely unnoticed, that year he became a U.S. citizen and received a promotion to Assistant Professor at Cornell.

As part of his research at the New York Hospital, he collaborated with Dr Herbert Traut, a gynaecological pathologist, eventually publishing their landmark book in 1943, Diagnosis of Uterine Cancer by the Vaginal Smear.