Doctors and researchers have established that the genes we are born with may increase our risk of developing certain types of cancer. For some people, becoming aware that they carry a cancer-causing genetic mutation may spur them to take preventive action. Women with BRCA1 and BRCA2 mutations may pursue surgery to help prevent breast cancer, for example.
Now, with the introduction of a technology called multigene panel testing, people can learn about not just one but many inherited mutations at once. One vial of blood can shed light on a spectrum of predisposition and risk.
We recently sat down with Mark Robson, Clinic Director of Memorial Sloan Kettering ’s Clinical Genetics Service, to ask him about who might benefit from this type of testing — and in what ways — as well as the pros and cons of pursuing this cutting-edge technology.
How does multigene panel testing work?
For years, doctors and researchers looked at the inheritance of one potentially cancer-causing mutation at a time. This meant that we sometimes missed the chance to identify mutations in a person who could have benefited from more insight into their risk for cancer. The process of looking for additional genes was time-consuming and expensive.
The multigene — also called multiplex — technology introduced in the United States in 2013 changed this scenario by enabling us to simultaneously examine dozens of cancer genes at a cost that is comparable to that of tests for individual genes.Back to top
Who might consider undergoing this testing?
While everyone has some risk of developing cancer, a small percentage of the population [no more than 5 to 10 percent] are genetically predisposed — and therefore at higher risk than the general public — to developing certain types of cancer because they’ve been born with DNA mutations that they inherited from their parents. These people and their families tend to have multiple cancers diagnosed at unusually young ages, and might benefit from knowing about the spectrum of their risk for the more than 50 hereditary cancer syndromes identified to date.
Multigene genetic testing looks for inherited mutations in a number of different genes, including ones associated with an increased risk of hereditary colorectal cancers, breast cancer, hereditary diffuse gastric cancer, uterine cancer, Li-Fraumeni syndrome, the childhood disease Fanconi’s anemia, and more.Back to top
What action can people take using what they learn from multigene panel testing?
Because many factors will affect whether you actually develop cancer, it’s important that a genetics counselor or other professional who specializes in hereditary cancer and cancer risk assessment help you figure out if you should get tested and how to interpret the findings.
Knowing more about potentially cancer-causing genes can, in some cases, give you and your family members a chance to do something to prevent or stop a cancer, if such measures are available. In many cases, however, next steps aren’t so clear, and the best treatment options aren’t known.
A drawback to multigene panel testing is that we don’t yet have enough information to guide people in prevention strategies for several of the genes tested. In other words, you may get information about having inherited a cancer risk that we don’t understand well or for which we don’t have any treatment strategies to offer. Or you may learn about genes of emerging risk, or variants of undetermined significance, for which we currently can’t offer a clear path or solution.
Information can be highly ambiguous, with no clear course of action for you to take. That’s why it’s essential that a genetics counselor work with you to interpret the results and explain all your options so you can make an informed choice.Back to top
What’s next in genetic testing for cancer?
In addition to learning about individual propensity and risk for various cancers, results from multigene panel testing have the potential to greatly expand our understanding of cancer if we put all the data in one place. In 2014, some of the commercial laboratories offering the test teamed up with experts from MSK and other academic medical centers to build the Prospective Registry of MultiPlex Testing (PROMPT).
This registry consolidates data in an exciting new way. Individuals and families who’ve been tested for inherited cancer-causing genetic mutations or genetic variants of uncertain significance can volunteer information — anonymously if they wish — about their results through this online portal.
By contributing altruistically to science, people might benefit not only themselves but also future generations.
Through this type of collaboration, we move scientists and researchers out of isolation and make it possible to quickly let people know about new or upcoming clinical trials and testing that might be of benefit to them — at the same time that we work toward new standards of care applicable to millions with hereditary cancers.Back to top