If a history of cancer in your family causes anxiety, that feeling is completely valid — and worth exploring. While lifestyle and environmental factors play a role, some cancers are linked to inherited gene changes passed down through generations. This is where genetic testing for cancer becomes valuable — it helps identify inherited mutations and provides insight into your inherited cancer risk.
The leading diagnostic centre in Chennai explains genetic testing for cancer by outlining key patterns in a family history of cancer — such as:
- Specific cancer types
- Ages at diagnosis
Recognising these signs is the first step toward making informed and proactive decisions about your health.
Who Should Get Genetic Testing for Cancer?
When you speak with a healthcare professional, they will take a detailed family history to assess your risk. Understanding what information matters most can help you prepare for that discussion.
Some of the most important indicators include:
Multiple Close Relatives With the Same or Related Cancers
A strong family history often involves several close relatives — such as parents, siblings, aunts, or uncles — on the same side of the family with cancers like
- Breast
- Ovarian
- Colorectal
- Prostate cancer
Cancer Diagnosed at a Young Age
A diagnosis before the age of 50 is a significant red flag — and may suggest an inherited cancer syndrome.
Multiple Primary Cancers in One Individual
This includes someone who has had two different cancers — or cancer occurring in both organs of a paired set, such as both breasts or both kidneys.
Rare Cancers or Unexpected Presentations
Certain cancers are uncommon and raise concern when they occur. For example, breast cancer in a man is a strong indicator that genetic testing should be considered.
A Known Genetic Mutation in the Family
If a close relative carries a known inherited mutation — such as BRCA1 or BRCA2 — this is a direct reason for other family members to consider testing.
Ashkenazi Jewish Ancestry
This ethnic background is associated with a higher likelihood of carrying certain hereditary cancer-related gene changes.
A Clear Pattern of Related Cancers Across Generations
Examples include breast and ovarian cancer appearing together — or colorectal and uterine cancers recurring within a family.
Recognising these patterns can feel unsettling — but they are not a diagnosis. Instead, they signal that it may be time to discuss genetic testing with a healthcare professional. While these signs suggest a possible hereditary link, it’s also important to understand that most cancers occur by chance — which we explore next.
Also Read: Genetic Testing for Disease Detection: Decoding the Benefits
Understanding the Link Between Genes and Hereditary Cancer
The majority of cancers are sporadic — meaning they arise due to random genetic changes influenced by lifestyle or environmental factors rather than inherited mutations. For example, excessive sun exposure damages skin cells and increases the risk of skin cancer — an environmental cause rather than a hereditary one.
Hereditary cancer, however, occurs when a person inherits a faulty gene from a parent. Each of us carries two copies of every gene — one from each biological parent. In hereditary cancer syndromes, one copy of a critical gene is already faulty at birth. This means it takes only one additional genetic change — often explained by the “second hit” theory — for cancer to develop. This is why cancers associated with inherited mutations often occur at younger ages.
Importantly, inheriting a mutation increases risk but does not guarantee cancer will develop. Genetic testing looks for known inherited mutations associated with specific cancer syndromes.
For example:
- Hereditary Breast and Ovarian Cancer (HBOC) syndrome is linked to BRCA1 and BRCA2 mutations and increases the risk of breast, ovarian, prostate, and other cancers.
- Lynch syndrome, associated with genes such as MLH1, raises the risk of colorectal and endometrial cancer.
It’s also essential to distinguish genetic testing for inherited risk from tumour genetic testing. Tumour testing is performed after a cancer diagnosis to guide treatment — whereas inherited genetic testing looks at lifelong risk and prevention. Once you understand the genetic basis of risk, the next step is navigating the clinical journey of the testing process itself.
The Process of Genetic Testing and Counselling Explained
Genetic testing for cancer is a structured medical process — not just a laboratory test.
It begins with
- A discussion with your GP or specialist, who may refer you to a genetic counsellor.
- A genetic counsellor plays a central role throughout the process. During pre-test counselling, they review your family history in detail, assess your personal risk, and explain what genetic testing can and cannot tell you. This session also provides space to discuss emotional concerns, as anxiety and uncertainty are common.
- Your counsellor will clearly outline the benefits, limitations, and possible outcomes of testing — ensuring you can make an informed decision. For this reason, written informed consent is required before testing proceeds.
- If you choose to go ahead, the test itself is simple and painless — usually involving a blood sample or saliva swab. The sample is analysed in a specialised laboratory to look for specific gene mutations. Results typically take two to four weeks — depending on the complexity of the test.
After results are available, post-test counselling is essential. Your genetic counsellor will help interpret the findings and guide you through the next steps.
Making Sense of Your Genetic Test Results
Genetic test results generally fall into three categories:
- Positive
- Negative
- Variant of uncertain significance (VUS)
Positive Test Result
A positive result means a gene mutation associated with increased cancer risk was found. This does not mean you have cancer or will definitely develop it. Instead, it allows you and your doctor to create a personalised prevention plan.
This plan may include:
- Enhanced or earlier screening — such as more frequent mammograms or colonoscopies
- Risk-reducing medications, where appropriate
- Preventive surgery — reserved for individuals at very high risk
Sharing a positive result with family members enables cascade testing — allowing relatives to check whether they carry the same mutation and take preventive steps if needed.
Negative Test Result
- A negative result means no known harmful mutation was found. However, this does not automatically mean your cancer risk is average.
- A true negative occurs when a known family mutation exists and you are confirmed not to have inherited it. In this case, your risk may be similar to the general population.
- An uninformative negative means no mutation was identified — but no known family mutation exists for comparison. In this situation, a strong family history alone may still place you at increased risk — and screening recommendations may differ from average-risk guidelines.
Variant of Uncertain Significance (Vus)
A VUS is a genetic change whose impact on cancer risk is currently unknown. This uncertainty can be stressful, but it is important not to make medical decisions based on a VUS alone. Over time, many variants are reclassified as more research becomes available, and your genetic counsellor will guide you on appropriate follow-up.
Regardless of the result, your genetic counsellor helps translate the information into practical next steps — and long-term health planning.
Taking Control of Your Health With Proactive Knowledge
World Cancer Day - Feb 4 serves as a global reminder to take proactive steps in health management. If you’ve been feeling anxious about your family history — understanding your genetic risk can transform worry into proactive health management. For individuals with certain risk factors, genetic testing for cancer provides clarity — and supports the creation of a personalised prevention plan.
This journey is best navigated with the guidance of a genetic counsellor or healthcare provider who can interpret results and discuss appropriate options. If you have a family history of cancer or concerns about your inherited risk — speak with a healthcare professional about whether genetic testing is right for you.
You can take the first step by contacting Anderson Diagnostics — a trusted diagnostic centre in Chennai, where expert guidance and advanced genetic testing help turn insight into informed, preventive care.