Cracking the Genetic Code of Breast Cancer
Cracking the
Genetic Code of Breast Cancer: What We Should Know
Submitted by:
Surabhi Ganga ( MSc. Human Genetics, Cytogeneticist
As we observe
Breast Cancer Awareness Month this October, there’s a growing focus on
understanding how genetic testing is transforming the fight against breast
cancer. Genetic tests can provide vital information about a person’s risk,
guide early detection, and even help prevent the disease before it starts.
While breast cancer remains a significant concern worldwide, the ability to
unlock secrets hidden in our genes is offering new hope and empowering us to
take control of our health.
A Genetic Test: What Is It?
A genetic test is a
simple medical test that examines your DNA
to search for alterations,ie mutations in
specific genes that are linked to a higher risk of diseases like breast cancer.
Some of the most commonly tested genes include BRCA1 and BRCA2, which are known
to increase the chances of developing breast and ovarian cancers when mutated.
This type of testing can help people understand whether they are more likely to
develop cancer and take steps to catch it early or even prevent it.
In fact, the
spotlight on genetic testing grew significantly after actress Angelina Jolie
publicly shared her decision to undergo preventive surgery because of her BRCA1
mutation. Her story raised awareness, but genetic testing is now about much
more than that—it’s about giving everyone the opportunity to learn their risk
and act on it.
Genetic Tests: The
Key to Unlocking Your Risk
Genetic tests can
analyze your DNA to check for mutations in several important genes, including
BRCA1, BRCA2, TP53, and PALB2. These genes play a crucial role in controlling
cell growth, and mutations can increase the likelihood of developing breast
cancer, sometimes even at a young age.
If a person tests
positive for a mutation in one of these genes, it doesn’t mean they will
definitely develop breast cancer,but it does mean their risk is higher. If you
carry a BRCA1 or BRCA2 mutation, regular screenings—like mammograms or
MRIs—begin earlier, giving you a head start in detecting any abnormal growths.
In some cases, women opt for preventive surgeries. This personalized approach
helps women—and men—take control of their health, whether through more frequent
screenings or lifestyle changes.
Advances in Genetic
Testing Technology
So, how does
genetic testing work? These tests use advanced techniques like Next-Generation
Sequencing (NGS), a powerful tool that can quickly analyze large sections of
DNA. This technology looks for mutations in multiple genes at once, making it
easier to detect high-risk genetic variations. For more complex mutations,
Multiplex Ligation-dependent Probe Amplification (MLPA) is used to detect
larger genetic changes that might otherwise be missed.
Thanks to these
technologies, genetic testing has become faster, more precise, and more widely
available than ever before, giving more people access to this life-saving
information.
The Role of the
HER2 Gene in Breast Cancer
Beyond BRCA
mutations, another major breakthrough in breast cancer research is the
identification of the HER2 (Human Epidermal Growth Factor Receptor 2) gene.
While not inherited like BRCA, HER2 is an important player in breast cancer
progression. HER2-positive tumors grow faster, but identifying this gene
through genetic testing allows for precise, targeted treatments. Tests like the
HER2/neu test use Immunohistochemistry (IHC) and Fluorescence In Situ
Hybridization (FISH) to determine HER2 status in tumors, helping doctors decide
whether targeted therapies like trastuzumab (Herceptin) should be used.
Beyond BRCA: New
Discoveries and Emerging Tools
While BRCA1 and
BRCA2 mutations are well-known risk factors, scientists are continually
discovering new genes and genetic variations that contribute to breast cancer.
·
Lifestyle Factors and Gene Expression (Epigenetics)
Recent studies suggest that while you can’t change your genes, lifestyle
factors such as diet, exercise, and environmental exposures can influence how
your genes are expressed. This field of study, known as epigenetics, shows that
even individuals with genetic predispositions might reduce their cancer risk
through healthy living, such as maintaining a balanced diet, avoiding smoking,
and exercising regularly.
·
Polygenic Risk Scores (PRS)
In addition to single-gene mutations like BRCA1 and BRCA2, scientists are now
developing polygenic risk scores (PRS) that consider multiple small genetic
variations scattered throughout the genome. PRS can provide a more nuanced
understanding of breast cancer risk by calculating how a combination of minor
genetic factors contributes to overall risk. This is especially helpful for
those without major mutations but who still want to assess their long-term
risk.
·
Genetic Testing for Non-Hereditary Cancer Risk
While BRCA1 and BRCA2 are associated with hereditary breast cancer, only about
5–10% of all breast cancer cases are linked to these genes. For the majority of
breast cancer cases, which are non-hereditary, genetic testing still plays a
role. These tests focus on somatic mutations in the cancer cells themselves,
helping doctors determine the most effective treatment, such as whether the
cancer might respond well to hormone therapies or targeted treatments like
Herceptin.
Not All Mutations
Lead to Cancer: The Importance of Counseling
One important thing
to remember is that not every mutation detected by a genetic test is dangerous.
Some gene variations are classified as “variants of unknown significance”
(VUS), meaning their impact on cancer risk is unclear. In these cases, genetic
counseling can help explain the results, ensuring that patients receive
accurate information without unnecessary worry.
Genetic counsellors
work with patients to interpret test results and develop a plan based on their
individual risk, providing much-needed support and guidance through what can be
a complicated process.
Looking to the
Future: AI and Genetic Testing
As technology
continues to advance, artificial intelligence (AI) is playing a larger role in
genetic testing. AI can help analyze huge amounts of genetic data and predict
the impact of lesser-known mutations, providing more accurate and comprehensive
assessments of cancer risk. This is an exciting area of development that
promises to further enhance the accuracy and usefulness of genetic testing.
Conclusion:
Knowledge is Power, Not Fear
Breast cancer is
one of the most common cancers worldwide, but the good news is that we now have
powerful tools, like genetic testing, to detect it early and even prevent it.
Genetic tests give individuals the ability to understand their risk and take action—whether
that means more frequent screenings, preventive treatments, or lifestyle
changes.
As we mark Breast
Cancer Awareness Month this October, it’s important to remember that knowledge
is the key to empowerment. Genetic testing is not something to fear—it’s a tool
that allows us to protect our health, make informed decisions, and live without
the unknown hanging over us. The future of breast cancer prevention is here,
and it’s in our DNA!.
References:
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Easton DF, et al. Genes, environment and cancer risk: the contribution
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Ebbesen KK, et al. Epigenetics and breast cancer: Role of
environmental factors. Carcinogenesis. 2019.
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Mavaddat N, et al. Polygenic risk scores for prediction of breast
cancer. Am J Hum Genet. 2019.
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Kruglyak KM, et al. Somatic mutations in breast cancer: Predictive
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