Large DNA Study Analyzed Genetic Risk to Develop Cancer

In the largest DNA study ever, scientists analyzed the genetic code of 200,000 people - half with cancer and the other half without. By finding the differences, the researchers could identify over 80 regions of the human genome so far that, when found in an individual, means an increased risk of certain kinds of cancer, including for example prostrate, breast and ovarian cancers.

According to a press release issued by Cancer Research UK, one of the study's funders, each of these alterations, called Single Nucleotide Polymorphisms (SNP), only raise the risk of cancer by a small amount; however, the 1 percent of the world's popuation that host a high number of critical SNPs could be as much as 50 percent more likely to develop prostate cancer and 30 percent more likely to develop breast cancer over the course of their life.

The researchers expressed hope that their massive study may lead to significant progress in detecting the disease, which could eventually (but probably rather soon, with the current rapid speed of progress) lead a simple blood test that would reveal what cancers a person has a genetic predisposition for, if any. It should be cautioned though that there is more then only genetic factors influencing the risk of cancer.

"By looking for people who carry most of these variations we will be able to identify those who are at the greatest risk of getting cancers and then targeting screening tests to these individuals," said Doug East, the study author and cancer Research UK scientist at the University of Cambridge.

The study revealed 23 new genetic variations that may lead to prostate cancer, 49 for breast cancer and 11 for ovarian cancer.

In addition to looking for variations, researchers looked for the SNPs that may influence different breast cancers to behave differently as well as regions that many influence the cancer risk for people with faults in the BRCA genes - a group known to be at greater risk for both breast and ovarian cancers.

"This groundbreaking international work highlights how complex cancer is," said Harpal Kumar, Cancer Research UK's chief executive. "Hundreds, if not thousands of genes are likely to play a role in how cancers start. But by understanding why some people seem to be at a greater risk of developing cancer we can look towards an era where we can identify them and take steps to reduce their chances of getting cancer or pick up the disease in its earliest stages."

For example, women who have a BRCA1 fault and most of the genetic variants linked to BRCA1 statistically have more than an 80 percent chance of developing breast cancer by the time they turn 80. For women with the BRCA1 fault but just a few alterations of it on top, this number drops to 50 percent.

Finally, researchers involved in the study identified a series of SNPs only associated with an especially aggressive type of breast cancer, which in turn may lead the way for new treatments.