What is Hereditary Cancer?
Cancer is called hereditary (or germline) when the cause of the cancer is a gene mutation that is present in every cell of a person’s body. An estimated 5-10% of cancer cases are known to be hereditary.
Today we know of a number of genes that cause hereditary cancer. When they contain a mutation (a genetic change in a particular gene compared to the average person). Two examples are BRCA1 and BRCA2, which significantly increase a person’s lifetime risk of getting breast, ovarian, or prostate cancer when they contain mutations that affect their normal function.
The other 90-95% of cancer cases are referred to as acquired (or somatic) cancers, because the genetic change (or mutation) that caused the cancer is present only in a single organ and was caused by external influences, such as exposure to toxic substances, radiation, adverse lifestyle, diet, or obesity. This type of cancer is typically not inherited by a cancer sufferer’s offspring.
BRCA1 gene defect
BRCA2 gene defect
Inherited cancer risk
About 12% of women in the general population will develop breast cancer sometime during their lives.
By contrast, 55 – 65% of women who inherit a harmful BRCA1 mutation will develop breast cancer by age 70 years.
Similarly, for women who inherit a harmful BRCA2 mutation, the chances are 45%.
How can I know whether I am at risk of a hereditary cancer?
The best way to know whether you are at an increased risk for a hereditary type of cancer is to consult a genetic counsellor. A genetic counsellor will look at your health-related family history and be able to estimate your risk and recommend genetic testing to rule out or ascertain the risk.
In general, you are considered at a higher risk if one of the following scenarios applies to you and your family members:
- Early onset breast cancer or triple-negative breast cancer below the age of 50
- Male breast cancer at any age
- Other early breast cancers
- Multiple primary cancers in one individual
- Family history of any cancer
What is Genetic Counselling?
Genetic counselling is a process to help individuals, couples, and families understand their risk of an inherited genetic condition to make informed health decisions. Healthcare professionals called ‘Genetic Counsellors’, with training in medical genetics and counselling provide genetic counselling consultations.
Why should I talk to a Genetic Counsellor?
- Multiple members in the family that have had cancer
- Family members that have had cancer at an early age
- Rare cancers are diagnosed
What happens at a Genetic Counselling session?
A genetic counsellor is specially trained to look at how diseases, including cancer are present in a family and have been passed on through the generations. Based on this information, the counsellor can estimate the risk of getting a disease of the individual that has been referred for counselling. In order to be able to estimate this risk, the genetic counsellor will
- take a detailed family history of all the diseases of immediate family members going back several generations
- explain the basics of genetics and how known hereditary diseases can be passed down through families
- recommend genetic testing if an increased risk has been identified and a specific test to ascertain that risk is available
Where can I find a genetic counsellor?
Our genetic counsellors are available for telephonic consultations across the country and available for in clinic consultations at major cities:
- New Delhi (NCR region)
Contact us to schedule an appointmentContact us
The Strand® Hereditary Cancer Test
A genetic test to determine cancer risk in advance.
When do you require the test?
After the GC has confirmed a risk of medium to high level based on your family history and other parameters.
What is the test about?
The Strand hereditary cancer test is a genetic test to determine cancer risk in advance. It indicates and estimates the risk for cancer predisposition in an individual based on evaluation of a number of genes associated with hereditary cancer risk, including BRAC1, BRAC2, and TP53. A detailed guide on the benefits of genetic testing for breast cancer is available in English and Hindi here.
About the test
The Strand® Hereditary Cancer Test evaluates a number of genes associated with cancer risk.
Some of the cancers tested are Breast, Ovarian, Prostate, Colon, Pancreatic and other rarer cancers.
Learn more about the Strand Hereditary Cancer Test
What type of sample is required?
Saliva in collection kits provided by Strand or blood in EDTA tubes (2-5ml). A Strand representative or clinic staff will assist you with sample collection and take care of all the shipping arrangements.
How long do I have to wait for a result?
The test report is delivered 4-6 weeks from receipt of the sample in our lab.
What does the test outcome mean?
The outcome of the test is usually an overall positive or negative cancer risk.
This information helps you take charge and manage your health better.
Should I worry about a positive test outcome?
Not at all! Knowing that you are at a higher risk of getting cancer equips you with the knowledge required to diagnose cancer early or even prevent cancer in the first place.
Genetic Testing for Hereditary Cancer – Frequently Asked Questions
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This is the story of Meena Nandal, a school teacher and life enthusiast, who was diagnosed with stage 3 ovarian cancer in her early 50s and fought back. When her cancer returned after just 18 months and had become resistant to chemotherapy, she looked for other options. She came to the Strand Center for Genomics and Personalized Medicine for genetic testing. She tested positive for a mutation in the BRCA2 gene that was categorized as a “variant of unknown significance”, a VUS. This is the technical term for a mutation that has not been investigated yet, and there was no scientific proof either way as to whether it caused cancer or not.
So, the scientists and doctors at Strand went to work and showed through a series of investigations and computer modelling that the mutation in question was indeed likely to have caused her ovarian cancer. This conclusion got confirmed when a genetic test performed on her younger sister, a breast cancer survivor herself, revealed that she carried the same mutation in the BRCA2 gene. In fact, even their brother was found to carry the mutation.
But that wasn’t the end of the story – clinical guidelines allow the prescription of a particular drug, known as a PARP inhibitor, to be prescribed in cases like this, where the patient’s cancer has become resistant to chemotherapy, and a BRCA gene mutation is confirmed. And needless to say, Meena fought the battle to tell her story. When this video was made, she had been free of cancer for 9 months without any of the side effects usually associated with cancer treatment. Thank you Meena for sharing your story, and being an inspiration to so many of us!
To know more about genetic testing and personalized medicine write to us at firstname.lastname@example.org or call us from India on +91 080 2309 5200
Thank you to Pinkathon for letting us film at the 2017 Bengaluru run.
Posted by Stay Ahead of Cancer on Tuesday, February 28, 2017