Cervical Cancer Screening: Which HPV Test Should Be Used--L1 or E6/E7?

Cervical cancer can and should be a historical disease. The reality, however, is that every year more than half a million women are diagnosed with cervical cancer and a quarter of a million die of this disease. The causal factor for cervical cancer is a persistent HPV infection and therefore a vaccine was developed: prophylactic HPV vaccination will reduce cervical cancer by 70%. Screening based on cytology will miss more than 40% of the abnormalities. The introduction of vaccination should lead to the reintroduction of cervical cancer screening based on HPV detection. Primary HPV screening followed by cytology will detect almost all abnormalities. Not all HPV tests, however, are the same! Clinicians are generally not aware that there is a huge difference among HPV tests. If a low grade lesion progresses to a high grade or invasive cancer, their HPV is likely to integrate. During integration L1 expression can be lost, but E6/E7 expression will always remain present. If the viral HPV is completely integrated then a L1 test looking for only L1 expression will miss this (pre)cancer, while the E6/E7 test will not miss it. HPV tests used in cervical cancer screening should be based on the early (E) and the late (L) genes in order not to miss the abnormality.