Three studies, published in the journal Nature Genetics, have uncovered ten genes that affect a man's risk of developing prostate cancer. The researchers hope that the discoveries will form the basis of a test that will predict men's chances of developing prostate cancer, as well as providing potential targets for drug development.
The three research teams - based in Britain, America and Iceland - compared the genomes of men with prostate cancer to those of a healthy control group looking for genetic 'variants' confined to the prostate cancer group. Two of the genes from the studies hold particular interest for researchers: MSMB, as it can be measured in the blood, making it particularly applicable to screening; and LMTK2, as it is seen as excellent target for treatment.
Following decades of frustration for prostate cancer researchers, data has begun accumulating rapidly in the past 12 months. A series of papers published in Nature Genetics in May 2007 uncovered 7 genes affecting prostate cancer risk. The latest work brings the total number of genes thought to be involved to 18.
The prostate is a small walnut-sized gland that secretes a clear fluid during ejaculation that aids both the transport of spermatozoa and its longevity once inside the vaginal tract. Cancer of the prostate is the second largest cancer killer in UK males, after lung cancer, with 10,000 men dying every year.
With no genetic markers, it has previously been impossible to instigate a wide-scale screening program in the UK to help reduce mortality. Men with a family history of prostate cancer are currently offered a test that measures their levels of Prostate Specific Antigen (PSA). Notoriously ineffective, the test only necessitates a biopsy in 10-15 per cent of the men taking it, with only two to three per cent then requiring treatment. Dr Ros Eeles, an oncologist at The Institute of Cancer Research who led the British effort, said that 'from a public health point of view, this could be very helpful because it will allow us to target scarce resources to where they are really needed'.
A recent American study, published in the New England Journal of Medicine, recommended the development of a test using five of the genetic variants found in the initial studies from 2007. They suggested the markers could predict a 9.5-fold increase in the risk for the disease in those carrying all five variants alongside a family history. It is thought that the new markers will increase the predictive power of this test.
Icelandic company DeCode genetics, which uncovered two of the most recently discovered variants, have begun offering a test based on eight of the markers for £250. Critics suggest, however, that this is far from an exhaustive screen. 'The variants have the potential to be developed into a genetic test. However, we consider that marketing of tests to the public is premature', said Dr Eeles. He added: 'Researchers need to determine how often testing was needed, and the psychological implications'. A more comprehensive screening program may require up to three years of further development.