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A Greek physician, zoologist and microscopist who was a pioneer in cytopathology and early cancer detection. He is renowned for his invention of the 'pap smear'.

Georgios Papanikolaou

In 1917, Papanikolaou and Stockard conducted an experiment on guinea pigs where they showed that the histologic cyclic changes during the estrus cycle in the reproductive tract also occur in the vaginal muscosa. They discovered that these changes could be detected through cytologic examination of vaginal smears. This groundbreaking technique, now known as the Papanikolaou technique, not only advanced our understanding of the estrus cycle but also led to the identification of an ovarian hormone.

Papanikolaou then turned his attention to studying the human reproductive system, with the invaluable support of his wife, Mary. Mary, an unpaid laboratory technician in the same lab, provided a daily vaginal sample for their research. She also processed her own samples in the lab for further analysis. Over a period of twenty-one years, Mary continuously contributed samples, and she even encouraged her friends to participate as well.

In 1920, Georgios Papanikolaou made a crucial discovery. He realised that he could differentiate between normal and malignant cells on the cervix by examining smears on the microscope slide. In 1925, funded by the National Research Council and the Maternal Health Committee, Papanikolaou enlisted 12 volunteers from hospital staff, along with several pregnant gynaecological and surgical patients, to conduct a systematic study of cervical cell morphology. These participants were regularly tested to track hormonal changes and diagnose early pregnancy. During his examination of a slide containing a smear from one participant's vaginal fluid, Papanikolaou experienced an exhilarating moment when he spotted abnormal cancer cells under the microscope. Reflecting on this discovery, he later wrote, 'The first observation of cancer cells in the smear of the uterine cervix gave me one of the greatest thrills I ever experienced during my scientific career'.

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