But not all smokers get lung cancer and not all people who eat cheeseburgers get bowel cancer and “other factors” have to be at play.
“This discovery rewrites the textbook explanation that cancer occurs due to human behavior combined with a little bit of bad luck to include one’s genetic makeup,” said Dr. Edwin Wang, a scientist at the University of Calgary.
“We believe that a baby is born with a germline genomic pattern and it won’t change, and that pattern is associated with a lower or higher cancer risk,” he said in a paper published in the journal Science Advances.
The germ line represents the cells that determine our children and the DNA that is passed on from parent to child.
It is the first time that scientists have described these highly specialized biological models applicable to cancer risk.
Wang found that DNA fingerprints could be classified into subgroups with distinct survival rates.
One of the seven germ lines offers protection from cancer development and the other six germ lines have a higher risk of cancer.
“It is interesting that one of these germ lines protects against the development of cancer and has appeared frequently in our analysis of genomes,” noted Wang, a professor in the CSM’s Department of Biochemistry and Molecular Biology.
“We know that there are people who can smoke and have an unhealthy lifestyle, but never get cancer, and this discovery could explain this phenomenon.”
For this research, Wang conducted a massive systematic analysis of over 26,000 germline genomes of individuals, about 10,000 people who had cancer and the rest without.
The samples include 22 distinct tumors, including lung, pancreatic, bladder, breast, brain, stomach, thyroid, and bone, and a dozen more.
The control group of people without cancer included genomic sequencing groups from Sweden, England and Canada.
The huge amounts of data were processed using machine learning.
Wang said between 5 and 10 percent of cancers are caused by specific gene mutations.
Think breast cancer and the inherited gene BRCA1 and BRCA2, a genetic mutation made widely known by actor Angelina Jolie.
“We found that a DNA fingerprint has been enriched tens to hundreds of times in the germline genomes of cancer patients, suggesting that it is a universal inherited trait that encodes cancer risk,” the scientist noted.
The research also found that another DNA fingerprint was highly enriched in cancer patients who were also tobacco smokers, indicating that smokers with that DNA fingerprint have a higher risk of cancer.
“I hope more studies will be conducted to expand this work so that it can eventually be put into practice by allowing doctors to inform patients of their cancer risk and how to take precautions to ensure a healthy life,” Wang said.