Damaged Inherited Genes Can Lead to Breast Cancer? It’s Time to Consider Genetic Testing!
A Worried Mother
Consider a 50-year-old mother who has been diagnosed with triple-negative breast cancer. She has received clinical treatment and her condition is under control. However, she begins to worry about whether her 20-year-old daughter might also face the risk of breast cancer in the future. Doctors suggest that this mother should undergo testing for BRCA1/2, the genes associated with triple-negative breast cancer. If the test result is positive, then her daughter should also consider genetic testing to determine whether she is a carrier of the BRCA1/2 mutation—just like the well-known actress Angelina Jolie—who carries a significantly higher risk of breast and ovarian cancer compared with the general population. If the answer is yes, then the daughter may need to consider preventive measures (including surgery) in the future to reduce her cancer risk and avoid following in her mother’s footsteps.
Undergoing preventive removal of both breasts and ovaries, as Angelina Jolie did, requires tremendous courage and a scientific understanding of hereditary breast cancer. For BRCA1/2 mutation carriers, bilateral mastectomy can reduce breast cancer risk by 90% and contralateral mastectomy reduces the risk of secondary cancer by 90%. Oophorectomy can reduce breast cancer risk by 50% and ovarian cancer risk by 90%.
The Angelina Jolie case highlighted one of the key benefits of genetic testing for hereditary breast cancer: prevention. Jolie’s decision triggered widespread public attention in the United States and worldwide, directly driving up the demand for BRCA genetic testing.
In fact, genetic testing plays an essential role in breast cancer risk assessment, screening, prevention, and treatment. It provides valuable information not only for prevention, diagnosis, and individualized treatment, but also for family members and future generations.
Therefore, whether for breast cancer patients or high-risk individuals, genetic testing is highly recommended.
One Damaged Gene Pair Can Trigger Tumor Formation
It is well known that human somatic cells (non-reproductive cells) contain 23 pairs of chromosomes and 3 billion base pairs, which carry genetic information fragments known as genes. In somatic cell events, a single pair of damaged genes can lead to tumor formation. In hereditary cancers, since one damaged gene is inherited, tumor formation occurs once the other normal gene is damaged. Therefore, individuals carrying hereditary cancer-related genes have a cancer risk five to ten times higher than that of the general population.
Dr. XUAN Linli, Chief of Medical Oncology at Jiahui International Cancer Center, recommends that when a person has one or more of the following risk factors, they should undergo genetic testing to evaluate their risk of hereditary breast cancer:
l Ovarian cancer at any age
l Triple-negative breast cancer
l Breast cancer before age 50
l Male breast cancer at any age
l Multiple primary breast/ovarian cancers
l Ashkenazi Jewish ancestry
l Relatives of BRCA mutation carriers
l Early-onset pancreatic or prostate cancer
According to Dr. XUAN, comprehensive testing packages covering 20 breast cancer susceptibility genes are now available, and results are scientifically interpreted in accordance with international standards to develop individualized risk management or treatment plans.
Different genetic mutations confer different levels of cancer risk. For example, the BRCA1 mutation—the one that led Angelina Jolie to undergo bilateral mastectomy and oophorectomy—can result in a 50–80% risk of breast cancer and a 40–60% risk of ovarian cancer. In contrast, a CHECK2 mutation confers a breast cancer risk of about 20%. Thus, genetic testing results must be further analyzed to determine the level of breast cancer risk.
If the Risk Is Higher Than the General Population, What Does That Mean for You?
For cancer patients, genetic testing can be used to understand tumor subtypes and guide clinical treatment plans. For high-risk individuals, genetic testing can help assess risk and enable early diagnosis. Different gene expressions point to different approaches in prevention and treatment.
How Will Jiahui Interpret Genetic Testing Results? Dr. XUAN will compare patients’ genetic test results against our large-scale genomic database. This process allows identification of pathogenic mutations as well as suspected pathogenic variants. At the same time, Dr. XUAN’s team will carefully consider three factors: 1. Which gene(s) the patient carries. 2. The patient’s family history (the same gene may present differently depending on family background and therefore requires careful evaluation). 3. The patient’s personal health history.
For high-risk individuals, doctors will provide preventive recommendations—including surgery, medication, and lifestyle modifications—to lower cancer risk and support long-term risk management. For cancer patients, this may mean adjustments to their clinical treatment plans.
Even without a family history of breast cancer, patients may still need genetic testing under certain circumstances, including but not limited to:
l No surviving relatives with cancer, but a first-degree relative with ovarian cancer;
l Few female relatives on the paternal side, while the patient herself has triple-negative breast cancer diagnosed under the age of 60.
The traditional belief that “without screening, no cancer will be found” or that “screening equals treatment” still dominates the way many people think about health management. Dr. XUAN emphasizes that “early detection and early treatment” remain the best strategies for cancer prevention and control. If you wish to make a change, start with understanding your genes.
Appendix 1: BRCA1/2 Carriers – Latest Guidelines on Screening and Prevention
l Training and education on breast self-examination, with monthly self-checks starting at age 18.
l Clinical breast examinations every 6 months starting at age 25.
l Annual MRI screening starting at age 25; at age 30, add both MRI and mammography.
l Consider prophylactic mastectomy.
l Recommend salpingo-oophorectomy
(for BRCA1 carriers starting at age 35; for BRCA2 carriers between 40–45).
l For carriers who do not undergo salpingo-oophorectomy: consider starting continuous ultrasound and CA-125 monitoring from age 35, or 5–10 years before the earliest family case of ovarian cancer (every 6 months).
l Consider preventive drug therapy for breast and ovarian cancer.
l Consider participating in exploratory imaging and screening studies.
Appendix 2: Recommendations for Patients with Non-BRCA1/2 Mutations
l High-risk breast cancer genes (TP53, PTEN, CDH1): discuss screening or prophylactic mastectomy.
l Moderate-risk breast cancer genes (PALB2, ATM, CHEK2, STK11): most patients can be monitored through screening; if there is a confirmed family history, discuss prophylactic mastectomy.
l For most moderate-risk carriers without additional family history: begin routine screening at age 40.
