Cervical cancer, the second most common malignancy, in women has a long pre-invasive stage of 10-13 years. This long pre-invasive stage forms the basis of screening for cervical malignancy, by detecting the premalignant lesions of the cervix. In the 1940s and 50s, it was understood that pre-invasive lesions precede invasive cancer of the cervix. George Papanicolaou, a Greek pathologist was indulged in studying exfoliated cells from the cervix and their transformations associated with menstruation. As one of his patients happened to be suffering from cervical cancer, he discovered that the abnormal cancer cells could be plainly detected on microscopic examination.