“Cancer and Genetics: Is It in My DNA?”

When someone is diagnosed with cancer, one of the first questions they often ask is,“Does cancer run in my family?”

While lifestyle factors play a big role, genes can also significantly influence your risk of developing cancer. Thanks to advances in science, we now know how certain inherited mutations and genetic changes increase cancer risk—and how you can take action early.

Let’s explore the fascinating world of genes, genetic testing, and cancer prevention.

🧠 What Are Genes—and How Do They Relate to Cancer?

Genes are sections of DNA that carry instructions for your body to grow, repair, and function. Sometimes, genes mutate or change—and not all mutations are bad. But some can affect how cells grow and divide.

When these changes disrupt the balance between cell growth and cell death, they can trigger cancer.

Cancer is fundamentally a genetic disease, caused by:

• Acquired mutations (most common) – develop over your lifetime due to environmental or lifestyle factors (e.g., smoking, radiation, infections)

• Inherited mutations (less common) – passed down from parent to child, present from birth

🧬 What Are Inherited Cancer Syndromes?

Inherited mutations account for about 5–10% of all cancers. These mutations increase your lifetime risk, but they don’t guarantee cancer will occur.

Common hereditary cancer syndromes include:

Syndrome	Gene(s) Involved	Cancers Linked
Hereditary Breast & Ovarian Cancer Syndrome	BRCA1, BRCA2	Breast, ovarian, prostate, pancreatic
Lynch Syndrome	MLH1, MSH2, MSH6, PMS2	Colon, endometrial, stomach, ovarian
Li-Fraumeni Syndrome	TP53	Breast, brain, sarcoma, adrenal
Familial Adenomatous Polyposis (FAP)	APC	Colorectal cancer

📌 Note: Not everyone with a gene mutation gets cancer—but their risk is significantly higher than the general population.

🔬 What Is Genetic Testing?

Genetic testing analyzes your DNA to check for mutations in cancer-related genes. It’s done using a blood or saliva sample, and results can guide both prevention and treatment strategies.

You might consider genetic testing if you:

• Have multiple family members with the same or related cancers

• Were diagnosed with cancer at a young age (under 50)

• Have rare cancers (like male breast cancer or medullary thyroid)

• Have a known family history of a gene mutation

✅ Benefits of genetic testing:

• Identify cancer risk early

• Enable targeted screening (e.g., early mammograms or colonoscopies)

• Guide preventive actions (e.g., risk-reducing surgeries or medications)

• Inform treatment decisions (some cancers with BRCA or mismatch repair mutations respond better to certain drugs)

⚠️ Important: Always undergo genetic counseling before and after testing to understand the results and implications for your family.

🧬 New Frontiers: Polygenic Risk and Tumor Genomics

In addition to single-gene mutations like BRCA, researchers are now exploring polygenic risk scores (PRS)—a calculation based on dozens or hundreds of genetic variations that, together, estimate your overall cancer risk.

Also, in those already diagnosed with cancer, tumor DNA testing (not inherited) helps:

• Identify targetable mutations (like EGFR, KRAS, ALK)

• Choose the most effective therapy (targeted or immunotherapy)

• Predict prognosis or treatment resistance

📉 Can Knowing My Genetic Risk Help Prevent Cancer?

Absolutely.

If you're found to carry a harmful mutation, you and your doctor can work together to:

• Increase early detection efforts

• Make lifestyle changes (weight, diet, smoking cessation)

• Consider preventive surgeries (e.g., mastectomy or oophorectomy in BRCA carriers)

• Offer testing to family members

📖 One major study (JAMA, 2020) found that women with BRCA mutations who had risk-reducing surgeries had a 90–95% lower risk of breast and ovarian cancer.

💬 Final Thoughts

Genetics isn't destiny—but it’s a powerful roadmap. Understanding your genetic risk can help you make informed decisions, catch cancer early, or avoid it altogether.

📍 At Dr. Rajiv Cancer Clinic, we offer comprehensive cancer risk assessments, genetic counseling, and personalized prevention plans—for you and your family.

– Dr. Rajiv Mohan, Medical Oncologist