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Not all breast cancer cases happen for the same reasons. Some occur without any family history, while others appear repeatedly within the same family. This often leads to an important question: is it just a coincidence, or is there a hereditary factor involved? Understanding the difference matters, because each person can have a different level of risk.
What Is Hereditary Breast Cancer?
Hereditary breast cancer is a type of cancer caused by genetic mutations passed down from parents to their children. These mutations are present from birth and can increase a person’s risk of developing cancer later in life.
The genes most commonly linked to this condition are BRCA1 and BRCA2 (Breast Cancer Susceptibility Genes). Normally, these genes help repair damaged DNA and keep cell growth under control. However, when mutations occur, this function is disrupted, making cells more likely to grow abnormally. As a result, individuals with these mutations have a higher risk of developing breast cancer, as well as other cancers such as ovarian cancer.
That said, not all breast cancer cases are inherited. This is why understanding the difference is so important.
What’s the Difference Between Hereditary and Non-Hereditary Breast Cancer?
In general, hereditary (inherited) and non-hereditary (sporadic) breast cancer differ in their genetic origin, age of onset, family history, and overall patterns.
Hereditary breast cancer is caused by inherited gene mutations, most commonly in BRCA1 and BRCA2. These mutations are present from birth and significantly increase cancer risk, but they only account for about 5–10% of all cases.
On the other hand, sporadic breast cancer develops due to genetic changes that occur over time, not because they are inherited. Factors like aging, hormones, and lifestyle play a much bigger role here, and this type makes up the majority of cases, around 90–95%.
Family history is another key difference. Hereditary breast cancer often shows a pattern within families, such as multiple close relatives being diagnosed with breast or related cancers. In contrast, sporadic cases usually do not have a clear family history.
There are also differences in age and tumor characteristics. Hereditary breast cancer tends to appear at a younger age and may show more aggressive biological features, such as higher cell proliferation rates (for example, Ki67 ≥25%). Some studies suggest that individuals under 54 with these characteristics are more likely to have BRCA-related mutations. Meanwhile, sporadic breast cancer is more common in people aged 54 and above and typically has different biological markers, with little association to BRCA1 mutations.
In terms of risk, individuals with BRCA gene mutations have a significantly higher chance of developing breast cancer compared to the general population. Meanwhile, sporadic cancer risk is more influenced by a combination of non-genetic factors, including lifestyle.
Which Genes Are Most Commonly Involved?
In hereditary breast cancer, the most commonly involved genes are BRCA1 and BRCA2, both of which play a role in repairing DNA and maintaining normal cell growth. When these genes carry inherited mutations, the risk of developing breast cancer, often at a younger age can increase significantly.
Other genes such as TP53, PALB2, and CHEK2 may also contribute, although they are less common. Still, it’s important to remember that these genetic mutations only account for a small percentage of total breast cancer cases.
So, if there is a family history, does that mean the risk will definitely be passed on?
If a Parent Has Breast Cancer, Will the Child Definitely Get It?
Having a parent with breast cancer can increase your risk, but it does not mean you will definitely develop the disease. In fact, only about 5–10% of breast cancer cases are hereditary, while the majority occur sporadically.
However, genetics can play a bigger role in certain groups. Studies show that inherited gene mutations may contribute to up to 25% of breast cancer cases in women under the age of 30. This is why risk at a younger age deserves more attention.
Family history still matters, but it should be understood in context. Having a first-degree relative (such as a mother, sibling, or child) with breast cancer increases risk more significantly, and screening may be recommended earlier, often about 10 years before the age at which the family member was diagnosed. Second-degree relatives (such as grandmothers or aunts) may also increase risk, but to a lesser extent. If multiple family members are affected or diagnoses occur at a young age, genetic testing such as BRCA testing may be worth considering.
So, having a family history does not mean you will definitely get breast cancer. Instead, it should be seen as a signal to be more aware and consider appropriate early detection strategies.
Conclusion
Not all breast cancer cases are caused by the same factors. A small percentage is linked to inherited genetic mutations like BRCA1 and BRCA2, which can increase risk from a younger age. However, most cases are sporadic and influenced by factors such as age, hormones, and lifestyle.
In other words, having a family history does not guarantee that you will develop breast cancer. It simply means it’s important to better understand your risk and take the right preventive steps.
KALGen Innolab, as a diagnostic laboratory, is committed to supporting breast cancer prevention and early detection through comprehensive testing services. With advanced diagnostic technology and experienced professionals, KALGen provides various screening and risk assessment options, including genetic testing for hereditary cancer such as KAL-Screen, as well as early detection services like SPOT-MAS. With the right and targeted testing, early detection becomes a key step in improving breast cancer outcomes.
References
American Cancer Society. (2023). Breast cancer risk and prevention. https://www.cancer.org/cancer/types/breast-cancer/risk-and-prevention.html
National Cancer Institute. (2022). BRCA gene mutations: Cancer risk and genetic testing. https://www.cancer.gov/about-cancer/causes-prevention/genetics/brca-fact-sheet
Putra, I. G. N. A., & Sudarsa, I. W. (2013). Management of breast cancer with BRCA gene mutation. Jurnal Harian Regional. https://jurnal.harianregional.com/eum/full-6294
MedicElle Clinic. (n.d.). Mengenal gen BRCA dan mutasi gen BRCA. https://www.medicelle.co.id/mengenal-gen-brca-dan-mutasi-gen-brca/
Fakultas Kedokteran Universitas Wijaya Kusuma Surabaya. (2020). Gambaran pemeriksaan BRCA sebagai upaya pencegahan kanker payudara. Prosiding Seminar Nasional COSMIC Kedokteran. https://prosidingcosmic.fk.uwks.ac.id/index.php/cosmic/article/view/4
Cancer Research UK. (2023). Breast cancer risks and causes. https://www.cancerresearchuk.org/about-cancer/breast-cancer/risks-causes
