Is Cancer Hereditary?

Medically Reviewed

What are genes?

Who should consider genetic testing?

What results can I expect from genetic testing?

What does it mean to have an inherited risk of cancer?

How can I get more information?

Key Takeaways

1. Most cancers are not hereditary! 75–85% are mainly due to chance, aging, and environmental factors.

2. Some cancers can be inherited through faulty genes. Certain faulty cancer-protection genes can increase a person's risk of developing cancer.

3. Genetic testing can identify people at higher cancer risk. It is more suited for patients with cancer diagnosed at a young age, multiple primary cancers, rRare cancers or tumours, three or more relatives on the same side of the family with similar cancers.

What are genes?

We have 25,000 genes in our body that we inherit from our parents. Half from our father and the other half from our mother. Genes are the instructions that our body reads to carry out different functions. Many of our genes function normally to protect us from various diseases, including cancer. A cancer protection gene that is not working well (faulty) can increase our risk for cancer. This can run in families and may be passed down.

Genetic testing can identify individuals and family members at increased risk of cancer

Who should consider genetic testing?

Individuals who meet any of the following conditions can consider genetic testing:

• Cancer diagnosed at a young age

• Multiple primary cancers

• Rare tumour or cancer diagnosis

• 3 or more relatives on the same side of the family with similar types of cancer

How do I undergo genetic testing?

A genetic counselling session will be offered to you to discuss genetic testing. It will involve a discussion with a genetic counsellor/genetics specialist to assess how likely a hereditary cause or a faulty gene may be identified in you. The benefits, limitations & implications of genetic testing will also be explained to you.