Fighting HPV could help cervical cancer develop
25th October
Scientists in Cambridge have found that methods used to treat the virus which causes cervical cancer, human papillomavirus (HPV), could be accelerating the development of the cancers caused by the disease. Their findings are published today in Carcinogenesis.
Although HPV often goes undetected, it can cause conditions that affect patients’ well-being, such as persistent genital infections. It is often desirable to treat these patients and various therapy options are currently being explored. These include treatments that can be applied locally, such as creams. They mainly work by inducing the body’s cells to make anti-virus proteins, particularly interferon. An alternative used in some countries is to administer interferon directly, although this has largely been discontinued in the UK because of side effects.
Now scientists, led by Dr Nicholas Coleman of the Medical Research Council Cancer Cell Unit in Cambridge, are showing that these treatments, though effective in clearing the infection in many cases, may make matters worse for some patients infected by HPV 16, one of the forms of the virus which is most prevalent and known to cause cancer in the cervix and elsewhere.
The scientists found that interferon caused rapid clearance of HPV 16 in its usual form, which is ‘free-floating’ in infected cells. However, this was accompanied by the emergence of cells bearing previously dormant fragments of HPV DNA that were not free-floating but integrated into the DNA of the infected cells. In these emerging cells the levels of virus proteins associated with cancer growth were greatly increased.
“Our data showed that this integrated form of HPV was present all along, but only became a threat when the interferon treatment wiped out the free-floating forms of the virus. As the integrated form is the one which encourages cancer growth, it looks as though treating HPV by provoking an interferon response can worsen disease in some cases,” said Dr Coleman.
“In the case of cervical cancer, it is vital to pursue screening, especially in patients who have been treated for HPV. Regular smear tests continue to be our best tool for preventing cervical cancer. Exciting work in vaccine development is also showing promise.”
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Ref: MRC/40/06
