Georgios Papanikolaou, Greek-American pathologist, invented the pap smear (died 1962)

Georgios Nikolaou Papanikolaou was a Greek physician, zoologist and microscopist who was a pioneer in cytopathology and early cancer detection, and inventor of the pap smear for detection of cervical cancer.

The Papanicolaou test is a method of cervical screening used to detect potentially precancerous and cancerous processes in the cervix or, more rarely, anus. Abnormal findings are often followed up by more sensitive diagnostic procedures and, if warranted, interventions that aim to prevent progression to cervical cancer. The test was independently invented in the 1920s by the Greek physician Georgios Papanikolaou and named after him. A simplified version of the test was introduced by the Canadian obstetrician Anna Marion Hilliard in 1957.