By Guest Blogger: Troy Moore, Chief Scientific Officer, Kailos Genetics
Examining
genetics for clues to cancer risk
Genetic
testing offers new hope to those with a family history of cancer, helping to
establish risk levels and pinpointing the best course of treatment for certain
cancers.
Yet
for all of its benefits, genetic testing is still in its infancy. It’s only been
25 years since the Human Genome Project was launched, and the secrets of human
DNA are still being unlocked.
The benefits of
genetic testing
Virtually
everyone can benefit from knowing more about their DNA, especially if there’s a
family history of cancer. You may have inherited more than your father’s
unibrow and
Aunt
Agnes’s china collection – there may also be a higher risk for cancer.
Because
family history is a primary indicator of risk, you should be aware of who in
your family had cancer and what types. Without genetic screening, it’s
difficult to know if you are in a high-risk category and should start early
screenings.
The genetic testing
process
Genetic
testing has become much simpler than in the past. Not only is it more
affordable, but some labs can process a test based upon a simple cheek swab.
The exception is if you are testing a tumor – a sample of the tumor will be
needed to evaluate those genetic cells.
Almost
any type of cancer has a set of DNA changes associated with it. Usually people
are tested for specific types of cancer based upon their family history or
environmental factors that may contribute to cancer (such as smoking).
Working
with a genetic counselor before you are tested can help you determine which
tests would be most useful. If your family history doesn’t indicate testing for
certain types of cancer, you might consider testing for the most common types of cancer – breast,
prostate, lung and colon. There is a strong knowledge base around those
cancers, and the tests are well proven. The information the tests provide can
be used to set an appropriate screening schedule based on risk.
Once
tested, your genetic counselor can also help you interpret the results; for
example, the counselor could explain that even though you have twice the risk
of the general population for a type of cancer, if the occurrence is very low
you probably don’t need to worry. They can also help to provide advice on how
to discuss your testing with your family. Because you share the same genes,
your genetic test can have implications for other members of the family.
Deciphering variants of unknown significance
The
human genome has been mapped, but there is still much to learn about genetic changes,
or mutations. After all, there are over three billion base pairs in the genome.
Imagine the genome map as a road map that shows major highways and roads but
doesn’t include smaller streets. As people travel those unmapped streets and
information is gathered, the road map becomes more informative and useful.
This
lack of information can be frustrating for people who have variants of unknown
significance (VUS). While occasionally the VUS may be totally unique,
frequently there just isn’t sufficient clinical data associated with it to know
how it affects your risk of developing cancer.
Having
a VUS doesn’t necessarily put you into a high-risk category; however, it does
mean that a physician won’t be able to use that part of your genetic
information to recommend earlier screenings or adjust a course of treatment. However,
it is important that this information is cataloged into a public database, so
that new insights about each VUS can be shared.
In
the past, there was only one company conducting genetic testing and they kept the
data they obtained proprietary. However, the National Institute of Health (NIH)
has established and maintains a repository where clinical researchers and
testing laboratories can deposit information about DNA changes and the criteria
they used to make an assessment.
As
more patient information is aggregated around a particular VUS, its meaning
will become clearer. That’s why growing the NIH database benefits everyone –
and helps add information around those gaps in the genome map.
Genetic
testing is yielding new insights and understands of the role genes play in
cancer risk and treatments. With the growth of this knowledge base, it will
become increasingly valuable in the future.