By next year it could be possible to sequence the entire coding regions of BRCA1 and BRCA2 genes, which can put women at risk of developing hereditary breast cancer, for as little as £10, Professor Graham Taylor, Head of Genomic Services at Cancer Research UK, told delegates at the British Society for Human Genetics last Wednesday. 'Next generation' sequencing technology could slash current prices by up to 99% and is poised to deliver groundbreaking advances in genetic diagnosis across a whole spectrum of inherited conditions, says Professor Taylor, who is trialling the approach in collaboration with colleagues from Yorkshire and Wessex Regional Genetics Laboratories.
When the Human Genome was first sequenced in 2003, it was an expensive and labour-intensive process, taking some eight years to complete and costing the UK taxpayer in the region of £3 billion. But in the five years since, cheaper, easier and faster sequencing techniques have been developed, allowing much larger stretches of DNA to be sequenced at just a fraction of the cost.
Professor Taylor said: 'The emergence of next generation sequencing technologies has largely been spurred on by the field of genomics, where scientists have been trying to unravel the genetic basis of many common diseases, such as diabetes and cancer, by scanning the entire genomes of thousands of individuals at a time. What we've done is take this technology and see if it can be used to look for gene changes in a tiny fraction of the genome, for example a single gene.'
It is estimated that 5-10% of breast cancer patients have an inheritable form of breast cancer due to a mutation in one of two genes known as 'BRCA1' and 'BRCA2'. In their 'normal' state, these genes protect against cancer within the cell. However, women who carry a mutation in either of the genes have up to an 80% chance of developing breast cancer during their lifetimes. Currently, women can be tested for defective copies of the two genes, but this involves full genetic sequencing, which can take weeks and is very expensive.
Next generation sequencing technology allows several samples of DNA to be screened at a time, meaning that hundreds of diagnostic samples can be sequenced in one week, compared to the 18-week turnaround time associated with traditional methods.
Pilot studies are already underway to examine the potential for next generation sequencing technology to be used to diagnose a range of hereditary cancers, with results expected early next year.
