Virus-fighter genes linked to cancer growth

Genetic evidence has been found which demonstrates that a group of virus-fighting genes also play a role in the development of cancer.

A study by the Wellcome Trust has focused on the role of the APOBEC genes, a family which controls enzymes that scientists believe originally evolved to help the human immune system fight off viral infections. However, researchers have theorised for some time that those specific enzymes also create a specific set of mutations which are present in more than half of all known types of cancer.

The team studied the genomes of breast cancers found in patients who had inherited a specific deletion in two of the APOBECgenes, which is believed to make them more susceptible to breast cancer. The findings showed that cancers found in women who had the deletion demonstrated far more mutations than those who did not, which indicates that the APOBEC genes being unable to control the enzymes effectively could play a role in the development of cancer.

"The increased frequency of this common cancer signature in breast cancer patients with APOBEC gene abnormalities supports our theory that these enzymes play a role in generating this mutational signature,” says first author Dr Serena Nik-Zainal of theWellcome Trust Sanger Institute.

Exposure to cancer-causing processes leaves a distinct pattern of genetic damage, known as a “signature”, on genomes and it is this which is believed to cause cancer. Each process leaves a different signature behind on the genomes of cancer cells, and much research into the disease has focused on identifying which signatures are related to specific causes.

Interestingly, the study also found that the deletion in the APOBEC genes may also have some benefits for certain individuals. The study found that just eight per cent of Europeans carried the deletion, but this figure shot up to 93 per cent of the population of Oceania. Researchers say this implies that in some populations, the deletion must also be to the individual’s advantage.