New gene variant lab discovery explains cancer risk increase
after scientists have been able to explain just how a gene variant
carried in 15 per cent of the population may increase the risk of
developing cancer.
Isolation of gene variants holds great promise for finding effective therapies for treating cancer. This information may help doctors identify those who are at high risk of the disease so they can be advised on ways of preventing its development.
The findings are exciting also because they suggest new treatment directions for a certain type of cancer that is common, but offers little hope of survival for patients.
Even though it is easy to identify the some 15 per cent of the population who have the harmful gene, which is called XRCC3 T241M, it is not meaningful to examine them since there are also other unknown factors that influence if this variant increases risk of cancer.
"The variant makes the cell motor sputter and mutate, so cancer can arise," says associate professor Thomas Helleday, who leads the research team at the Department of Genetics, Microbiology, and Toxicology, >Stockholm University.
"On the other hand, we can possibly make use of the faulty variant to custom design new treatments in the future. And even if this doesn't happen, it's nevertheless important to understand the mechanisms that make certain individuals more susceptible to cancer than others," he added.
Normally our genes have to be divided into two perfectly identical copies when a cell divides. The unfortunate variant causes a defect in the division of the genetic material (mitosis), which means that a daughter cell may get too few or too many genes.
If a daughter cell does not receive a gene that prevents cancer, a so-called tumour suppressor gene, then a cancer can grow. One defence mechanism against cancer is for a cell that gets faulty genes to commit suicide (apoptosis).
The defect caused by the unfortunate variant when it divides the genes is so tiny that the suicide mechanism does not detect the fault, which allows the cell to continue its growth into a cancer.
"The variant causes just a tiny defect that cannot be detected by the defence mechanisms against cancer. Just as in life, minute mistakes can lead to fatal consequences if they are not discovered," said Helleday.
As scientists identify more genes that impact on cancer development, the prospect of a a comprehensive genetic test to accurately assess the risk of inheriting the disease becomes possible.
Identifying the first of a new set of cancer genes puts researchers in a much better position to tackle different types of cancer, both through testing high-risk groups and eventually through new clinical strategies.
