Date：2020-10-07

Breast cancer is currently the third leading cancer killer after lung cancer. It is also the most common cancer among women. On average, 1 in 14 Hong Kong women will get breast cancer in lifetime*. There are about 4,000 new cases of breast cancer in Hong Kong each year, including men and women, and this number is still increasing every year. Breast cancer is considered to be a highly hereditary cancer and 10% of. This article will provide information on the heredity of breast cancer.

*Reference: Hong Kong Cancer Registry, hospital Authority. Female Breast Cancer in 2018. Last updated: Oct 2020.​

Is Hereditary Breast Cancer Common?

Genetic inheritance plays an important role in the development of breast cancer. About 10% of patients have inherited mutated genes. Patients with breast cancer gene mutations have a 10-fold higher chance of developing breast cancer. The most common genetic mutations in breast cancer occur in the BRCA 1 and BRCA 2 genes. When BRCA 1 & 2 mutates, it increases the risk of breast cancer or even other cancers, such as ovarian cancer and prostate cancer.

BRCA 1 & 2 gene mutations are inherited in an autosomal dominant manner, meaning if the child gets the abnormal gene from only one parent, the child will inherit the mutated gene and has a higher risk of getting cancer. Whether the BRCA gene mutation is found in a male or a female, it has a 50% chance of inheriting the BRCA 1 & 2 gene mutation to the next generation.

Does it mean I will get Breast Cancer if I have BRCA gene mutations?

To answer this question, we must first understand the role of BRCA genes. BRCA 1 and BRCA 2 are genes responsible for suppressing tumours. If BRCA 1 and BRCA 2 genes undergo genetic mutations, it means that they will not be able to suppress tumours and the risk of getting cancer will increase significantly.

Therefore, the detection of BRCA 1 & 2 gene mutation does not necessarily mean that you will get breast cancer. It means that people with BRCA 1 & 2 gene mutations have a higher risk of developing related cancers, such as breast cancer, ovarian cancer, and prostate cancer.

A well-known BRCA gene mutation carrier is the famous Hollywood movie star, Angelina Jolie. After considering the history of breast cancer in her family, she was tested for the BRCA1& 2 gene and found that she had inherited a BRCA gene mutation. She realized that her lifetime risk of breast cancer was as high as 87%, therefore, she decided to undertake a preventative double mastectomy.

The above image shown CoGenesis®BRCA genetic test sample report.

Tackle Hereditary Breast Cancer through Precision Medicine

If BRCA 1 & 2 gene mutation is detected, it does not mean that preventative double mastectomy must be undertaken as Angelina Jolie did. You can choose to take preventive medicine treatment or regular breast cancer screening.

According to the recommended procedures from The National Comprehensive Cancer Network (NCCN), if BRCA mutated genes are detected, people should undergo a clinical breast cancer exam every 6-12 months and an X-ray mammogram screening every year or MRI to detect cancer as early as possible.

The World Health Organization confirms that early diagnosis can reduce breast cancer mortality. The earlier detection of hereditary breast cancer can avoid delays in treatment, the higher the chance of breast cancer being cured. In this way, the mortality rate due to breast cancer can be greatly improved, and there is no need to fear of hereditary breast cancer.

For more information about breast cancer mortality, please refer to the next article: Breast Cancer Risk Factors that Cannot be Underestimated: Prevent Breast Cancer by Understanding the Risks

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