Research shows that the risk of hereditary cancer is explained not only by mutations in genes, known as oncogenes and tumor suppressor genes, but by variations in the DNA that controls the expression of these genes that can also boost the disease.
This DNA that exercises regulatory functions was called 'junk DNA' because it does not encode proteins.
The scientists investigated 846 genetic changes within non-coding stretches of DNA, identified by previous studies such as those that affect cancer risk.
These changes consist of the genetic replacement in the particular positions in the human genome where a single letter of the genetic code varies between people. They are called single nucleotide polymorphisms (SNPs).
In all, the scientists examined more than six million genetic variants in 13 different body tissues.
It turned out that unlike mutations in DNA coding that are rare, but significantly increase the risk of cancer, non-coding SNPs are relatively common among the population, but only slightly increase the risk of cancer.
The study also revealed that these SNPs with cancer risk tend to be located specifically in regions that regulate the immune system and tissue-specific processes.
"What we have found is surprising," said Professor John Quackenbush, principal investigator of the study.
"Our results show that small genetic variations work collectively to subtly change the activity of genes that drive cancer," he said, expressing the hope that this approach could one day save lives "helping to identify people at risk of cancer, as well as other complex diseases. "
The researchers plan to develop models based on artificial intelligence to better predict cancer risk.
They also aim to study in detail the variations of SNPs that regulate the expression of many genes relevant to cancer development and use them to test new treatments.