A new study, in collaboration with Institut d’Investigació Biomédica de Bellvitge (IDIBELL), has found that gene changes occur up to five years before the detection of breast cancer, paving the way for treatments aimed specifically at reversing changes in susceptible genes before cancer occurs.
Breast cancer is the most common cancer in the UK with around 50,000 people diagnosed each year.
Published today in Carcinogenesis, the study was based on a group of 36 identical twin pairs from TwinsUK, based at King’s, the biggest adult twin registry in the UK, where one twin had developed breast cancer and the other had not. Comparing DNA samples from each twin, collected before and after the diagnosis of breast cancer, as well as samples from breast tumours and breast cancer cell lines, the research team found significant chemical changes in around 400 sites in the affected twin. Of these, scientists identified the DOK7 gene was identified as most likely to be directly involved in the development of breast cancer. On average, these chemical changes took place five years prior to the diagnosis of breast cancer.
Identical twins such as those at TwinsUK are ideal for studies of this nature as theyshare 100 per cent of their genes. Therefore, any difference between twins is attributable to environmental factors or chemical changes to their genes. These chemicalchanges in the way genes are expressed is called epigenetics.
Crucially, the DOK7 gene identified in this study can be switched on and off epigenetically, says Professor Tim Spector from the Department of Twin Research & Genetic Epidemiology at King’s, who co-authored the research paper.
Professor Spector said: ‘The identification of the DOK7 gene offers possibilities for the prediction and treatment of breast cancer and other common illnesses such as diabetes, Alzheimer’s disease and arthritis. In the future screening of epigenetic changes in key genes followed by drug treatments could be commonplace. Our twin studies are a great way of detecting these small but important differences between sisters and we hope to explore many other diseases.’
Dr Manel Esteller, Head of Epigenetics at IDIBELL, said: ‘An epigenetic alteration associated with an increased risk of breast cancer can be detected in the sick twin before theclinical diagnosis.’ The next step for researchers will be identifying the exact function of the DOK7 gene.
Dr Esteller added: ‘We believe the DOK7 gene is a regulator of tyrosine kinases, an antitumor drug target already used for the treatment of breast cancer. If DOK7 performs this function, new studies to test drugs for tumours resistant to chemotherapy could take place in the future.’
Notes to editors
Professor Tim Spector is available for interview.
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View the Carcinogenesis paper.