The team studied the genomes of breast cancers in patients with a specific inherited deletion in two of these APOBEC genes.
Dr Serena Nik-Zainal, first author from the Wellcome Trust Sanger Institute, said 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.
The new evidence, from a study of a million mutations in 2,680 cancer samples, suggests APOBEC
proteins may be one important trigger.
The research conducted by the National Institutes of Health has found that APOBEC mutations can outnumber all other mutations in some cancers, accounting for over two-thirds in some bladder, cervical, breast, head and neck, and lung tumors.
corresponding author of the paper, said that scientists knew the main functions of APOBEC cytosine deaminases were to inactivate viruses that attack the body and prevent ancient viruses present in the human genome from moving around and causing disrupting mutations.
But HIV has evolved a way to overcome restriction using an accessory protein called Vif (virion infectivity factor) to degrade the APOBEC proteins and allow the virus to spread.
This suggests that the interaction between Vif and these antiviral APOBEC proteins could be blocked with a drug that would shield the Vif interaction region," Albin says.
These enzymes, known as APOBECs
, can be activated in response to viral infections.