Viruses found in smear tests may be the key to preventing cervical cancer, which kills 270,000 women globally every year, according to Manchester researchers.
There are more than 100 certain types of cervix viruses also known as Human Papilloma Viruses (HPV), 14 of which can lead to an infection causing cancer.
However, after taking smears from both HIV positive and negative Kenyan women, researchers at the University of Manchester have found that one type of HPV (type 53) was never found in women who suffer from cervical cancer.
They found high numbers of type 53 in normal cervical smears from both HIV positive women, but this was rarely found in women with cervical cancer.
Dr Ian Hampson, senior lecturer in Viral Oncology from the University of Manchester who lead the study, said: “It is well known that HIV increases the number of different types of HPV found in any one patient. This implies that HIV opens the door for infection with multiple types of HPV.
“If only high-risk types of HPV are present, these will undoubtedly accelerate progression to cancer whereas if other types (type 53) are also present they may actually compete with the high-risk types to inhibit progression to cervical cancer.”
In Kenya it is the most common malignancy accounting for between 18% and 23% of all diagnosed cases of cancer.
The results were analysed by Dr Ian Hampson, Dr Lynne Hampson and Dr Innocent Orora Maranga at the university’s Viral Oncology Laboratories at Saint Mary’s Hospital.
Dr Hampson said the study suggested one possible explanation for why, in spite of a large increase in the numbers of HPV infections in HIV positive African women, there was not a corresponding increase in numbers of cases of cervical cancer.
This could also explain why another African study had actually shown the risk of developing one specific type of cervical cancer actually dropped in HIV-positive women.
The researchers now plan to do more research in this area and Dr Hampson said: “Our study was quite small and more research with larger sample numbers is now needed.
“We also need to work out exactly how one type of HPV might suppress the cancer-causing properties of another.
“If it can be proved that HPV type 53 can inhibit the cancer-causing properties of other high-risk types of HPV, this could potentially form the basis of a simple biological therapy to prevent this disease.
“This could be extremely useful in low resource countries who cannot afford expensive HPV vaccines.”
Picture courtesy of AJC1 via Flickr, with thanks
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