Improved cervical smear assessment using antibodies against proteins that regulate DNA replication

Carcinoma of the cervix is one of the mast common malignancies. Papanicolao u (Pap) smear tests have reduced mortality by up to 70%. Nevertheless their interpretation is notoriously difficult with high false-negative rates and frequently fatal consequences. We have addressed this problem by using aff inity-purified antibodies against human proteins that regulate DNA replicat ion, namely Cdc6 and Mcm5. These antibodies were applied to sections and sm ears of normal and diseased uterine cervix by using immunoperoxidase or imm unofluorescence to detect abnormal precursor malignant cells. Antibodies ag ainst Cdc6 and Mcm5 stain abnormal cells in cervical smears and sections wi th remarkably high specificity and sensitivity. Proliferation markers Ki-67 and proliferating cell nuclear antigen are much less effective. The majori ty of abnormal precursor malignant cells are stained in both low-grade and high-grade squamous intraepithelial lesions. Immunostaining of cervical sme ars can be combined with the conventional Pap stain so that all the morphol ogical information from the conventional method is conserved. Thus antibodi es against proteins that regulate DNA replication can reduce the high false -negative rate of the Pap smear test and may facilitate mass automated scre ening.