Scientists have found that women who carry a particular variation of the tumour suppressor gene p53 are seven times more likely to develop cervical cancer that those who do not. The researchers' findings are published today (21 May 1998) in the science journal Nature*.
The work was carried out by scientists from the Imperial Cancer Research Fund (ICRF) Skin Tumour Laboratory and Department of Medical Microbiology at St Bartholomew's and Royal London Hospital School of Medicine and Dentistry, London, the International Centre for Genetic Engineering and Biotechnology, Italy, and the Institute for Parasitology and McGill Cancer Centre, Quebec, Canada.
Doctors already know that infection by certain types of the Human Papillomavirus (HPV) is almost essential for cervical cancer to develop. Major advances have been made in understanding how these viruses cause cancer. However, much less in known about how an individuals' genetic makeup may contribute to cervical cancer development.
P53 is a key control point in the body's defence against tumour formation. It protects the genetic information in the cells from things which can damage them such as ultra violet radiation or certain chemicals. If p53 goes wrong then a cell has a greater chance of becoming cancerous.
Dr Alan Storey, leader of the ICRF research team, explained: "P53 is often defective in many forms of cancer but in cancers caused by the Human Papillomavirus (HPV) it is usually normal. Instead, HPV produces a protein, called E6, which stops p53 from working correctly."
People can carry one of two variations of the p53 gene, p53Arg or p53Pro. The researchers found that p53Arg is more easily inactivated by the HPV protein. This suggested that people who carry only p53Arg might be less well protected against the effects of HPV.
Said Dr Storey: "We found that cervical cancers resulting from HPV infection
were significantly more likely to occur in women who had only p53Arg.
Contact: Christine Suggars
Imperial Cancer Research Fund