Whole-genome sequencing may improve cancer diagnosis

Two US studies have demonstrated how whole-genome screening can help improve cancer treatment and diagnosis. The researchers claim to have taken a major step towards using this type of screening to help predict patients' responses to different treatment based on their genetics.

In one of the studies, researchers from the University of Alabama sequenced the genome of a woman with leukaemia using cells taken from her skin and bone marrow. Within six weeks, the technique revealed genetic defects that would have remained undetected by conventional diagnostic tests.

This led to the patient's treatment plan being changed from bone marrow transplantation to a targeted chemotherapy regime. The treatment proved successful and the patient is now in remission.

The second study looked at a woman who had died of breast cancer and ovarian cancer after a relapse. By obtaining the patient's genomic sequence, the researchers discovered she had several previously-undetected genetic traits. Her children can now be screened to see if they have inherited these traits so they can take preventative measures, such as pre-emptive mastectomy, if necessary.

Professor Boris Pasche, deputy director at the Birmingham Comprehensive Cancer Centre at the University of Alabama, and one of the lead scientists in the studies, explained: 'If patients have certain genes, they may not respond to certain treatments. But whole-genome sequencing gives a full picture of the genetic make-up of the tumour and the patient, and it may allow the physician to target a new treatment'.

Following completion of the Human Genome Project in 2003, some people believed that unlocking the human genome could lead to new cures for many diseases and personalised treatments. However, although a useful tool in pre-clinical research, the cost of whole-genome sequencing has been largely prohibitive.

As the technique becomes automated and more widely used in research, the cost of whole-genome sequencing may fall until it becomes a viable method for cancer diagnosis.

'Prices are still dropping very rapidly; in the next 10 years, it will cost less than US $10,000, and it certainly will be more affordable in the next five years', said Professor Pasche. He added: 'These cases of personalised genomic medicine are just some of the first examples of what will likely be commonplace in the near future'.

The studies were published in the Journal of the American Medical Association (JAMA).