On the trail of missing genes and cancer clues
By: Erin Allday
San Francisco Chronicle
March 3, 2020
Scientists have long known that some people are more likely to get cancer because they’ve inherited mutations in key genes from a parent.
Those families with predisposing genetic mutations tend to get certain types of cancer more often than the general population. For example, families with mutations in the BRCA1 or BRCA2 genes are at increased risk for breast and ovarian cancer.
Now, an international team of researchers has identified dozens more genes that may be involved in predisposing people to cancer. The study, published Wednesday in the journal Nature, identified 97 new gene mutations linked to an increased cancer risk.
“We found that one in five people carry at least one of these predisposing mutations,” said study senior author Michael Y. Ni, a professor of biochemistry and molecular biology at UC Berkeley.
Some of the newly identified genes are involved in well-known cancer-predisposing syndromes, such as Lynch syndrome, which raises the risk of several types of cancer, including colon cancer.
But many of the genes are not associated with any known cancer syndrome. That suggests that there are many more people out there who are at increased cancer risk but don’t know it.
“We expect that there are a lot of families out there who have these predisposing mutations and they don’t have a clue,” Ni said.
The study was conducted by scientists at the University of California, Berkeley; the Cancer Genome Atlas Research Network; and more than 100 other institutions around the world.
Scientists analyzed the genomes of more than 15,000 cancer patients and more than 29,000 people without cancer. They looked for variations in the DNA that were more common in people with cancer than in those who didn’t have the disease.
They identified 152 variations in 97 genes that were linked to an increased cancer risk.
Some of the variations are quite rare, occurring in just 1 in 100,000 people. But others are much more common, occurring in as many as 1 in 500 people.
The vast majority of the variations — 141 of the 152 — are what are known as “loss of function” mutations, meaning they prevent a gene from working properly.
“What that really means is that the gene is not providing its normal function of protection against cancer,” said study lead author Li Ding, a professor of pathology at the Johns Hopkins Kimmel Cancer Center.
Ding said it’s not clear yet how most of the newly identified genes work to increase cancer risk. In some cases, the genes may be involved in repairing DNA damage. In others, they may help regulate cell growth or death.
More research is needed to understand the role of each gene and how best to use that information to protect people with predisposing mutations, the authors said.
“These are all clues,” Ni said. “The challenge now is to turn these clues into knowledge that can be translated into actionable medicine.”
Missing genes and cancer clues
Scientists have long been searching for the origins of cancer, and recent discoveries have led them to believe that missing genes may be to blame.
It has long been known that cancer can be caused by damaged or mutated genes. But what has been less understood is why some people are born with missing genes that put them at increased risk for the disease.
Now, new research is beginning to shed light on this question. A team of scientists from the United States and Japan has found that a missing gene called DICER1 may be a key player in the development of several types of cancer.
DICER1 is a gene that helps to regulate the production of small RNA molecules called microRNAs. These microRNAs play an important role in many biological processes, including the regulation of gene expression.
The team found that people with a mutated form of DICER1 are more likely to develop breast cancer, ovarian cancer, and certain types of brain tumors. They believe that the missing gene causes a build-up of harmful microRNAs in the cells, which leads to the development of cancer.
This discovery could have important implications for the prevention and treatment of cancer. If we can find ways to target the missing gene, we may be able to reduce the risk of cancer or even prevent it from developing in the first place.
This is an exciting area of research, and we will be sure to keep you updated on any new developments.