Antibodies to HPV-16 E6 and E7 proteins as markers for HPV-16-associated invasive cervical cancer.

Transforming proteins E6 and E7 of human papillomaviruses (HPVs) are consistently expressed in HPV-associated cervical cancers. In ELISA with four HPV-16 E6-E7 peptides, patients with HPV-16-associated invasive cervical cancer (group 1) had a greater seroreactivity than all other groups, which included patients with HPV-16-associated cervical intraepithelial neoplasia, invasive cervical cancer patients without HPVs, and unaffected controls. A larger proportion of group 1 sera, as compared to sera of all other groups, was reactive with at least one peptide (49% vs 17-27%), and with two or more peptides (22% vs 0-6%). A clear difference between group 1 and all other groups was also found for high ELISA absorbance values to at least one peptide (22% vs 0-8%). This high seroreactivity of group 1 sera was confirmed by a radioimmunoprecipitation assay with in vitro transcribed and translated HPV-16 E7 protein. Sera from 50% of group 1 but only 3% of controls were reactive in this test. Antibodies to HPV-16 E6 and E7 proteins appear to be virus-specific and disease state-specific markers of HPV-associated cervical cancer.