Objective: Infection with oncogenic human papillomaviruses (HPVs) is the most important cause of cervical cancer worldwide. After infection there is a long latency period of at least 10 to 15 years during which cervical cancer develops in a small proportion of originally infected women. Up to 50% of these women have at diagnosis antibodies to the HPV oncoproteins E6 and E7, which are rarely found among healthy women. Our purpose was to evaluate whether antibodies to HPV16 and HPV18 E6 and E7 proteins are useful for early diagnosis of cervical cancer by measuring the antibody response in women in whom cervical cancer later developed.
Study design: A joint serum bank of 550,000 Swedish, Norwegian, and Finnish women was followed up for 0.5 to 20 years, after which 178 invasive cervical carcinoma (ICC) cases, 150 of whom had squamous cell carcinoma (SCC), and 527 controls were identified. Antibodies to HPV16 and HPV18 E6 and E7 proteins were determined by tag enzyme-linked immunoassays.
Results: HPV16/18 E6 and E7 antibodies were detected infrequently (7.0%) in women in whom SCC later developed and yielded a moderately increased estimate of associated relative risk (odds ratio 2.7, 95% CI 1.1-6.4). Sensitivity of the combined antibody tests for the detection of occult SCC varied between 6% and 14% but was not related to time lag between serum sampling and cancer diagnosis.
Conclusion: HPV16/18 E6 and E7 antibody responses are not sensitive markers of occult cervical cancer.