Professor Suzanne Garland, A/Professor Dorota Gertig, Professor John Wark, A/Professor Sepehr Tabrizi, Professor Marian Pitts, Dr Bircan Erbas
The cause of cervical cancer (neck of the womb) is a virus called
human papillomavirus (HPV). This virus is extremely common, with many
sexually active women being infected early in their sexual life.
women however clear the virus. In a small proportion of women the virus
becomes persistent and can lead to abnormal cellular changes of the
cervix as it is picked up on a Pap smear. Treatment of these
abnormalities prevents development of cancer. Why some women develop
persistent infection and others not is unknown.
Similarly we do
not understand why some women develop cancer and others do not. It is
recognized that those who smoke, long-term use of the oral
contraceptive pill, have other infections such as Chlamydia and genital
herpes are more at risk of progression. There may be some genetic
factors also which determine why some women once infected have chronic
infection with the ultimate development of cancer.
One way to
evaluate environmental from genetic effects is to study twins. If the
risk is greater in twins in general it is more like to be due to
genetics. This is particularly so if the risk is greater in identical
twins as compared to non identical twins. The study proposes to study
twins with abnormal Paps (as a likelihood of underlying chronic
infection from HPV), to define the HPV they may have been infected
Another way to see if they have had infection previously
will be to take a blood test. Twin pairs whereby both have been
infected with HPV will be compared for:
- the development of persistent infection with HPV (2x tests positive at least 12 months apart); and
- development of abnormal cells on Pap suggesting high-grade
abnormality (the lesion recognized occurring before cancer develops).
We will compare the outcome for 1 and 2 above and link this with
identical versus non-identical status, plus various environmental risk
factors (these will be determined by a questionnaire give to the women).