What's the Difference?

BRCA (Breast Cancer gene) and HER2 (Human Epidermal Growth Factor Receptor 2) are both genes associated with breast cancer, but they play different roles in the development and progression of the disease. BRCA genes are responsible for producing proteins that help repair damaged DNA and maintain the stability of the cell's genetic material. Mutations in BRCA1 or BRCA2 genes can increase the risk of developing breast and ovarian cancers. On the other hand, HER2 is a protein that promotes cell growth and division. Overexpression or amplification of the HER2 gene can lead to uncontrolled cell growth and aggressive forms of breast cancer. While BRCA mutations are inherited, HER2 overexpression can occur spontaneously in breast cancer patients. Both BRCA and HER2 are important biomarkers in breast cancer diagnosis and treatment, but they have distinct roles in the disease's biology.


FunctionTumor suppressor genesOncogene
Associated CancersBreast, ovarian, prostateBreast, gastric, ovarian
PrevalenceApproximately 1 in 400 individuals carry a BRCA mutationHER2 overexpression occurs in about 20% of breast cancers
TestingGenetic testing for BRCA mutations is availableHER2 testing is done to determine HER2 status in breast cancer patients
TreatmentTargeted therapies, surgery, chemotherapyTargeted therapies, surgery, chemotherapy

Further Detail


BRCA and HER2 are two important genes that play a significant role in the development and progression of certain types of cancer. While both genes are associated with increased cancer risk, they differ in their functions, prevalence, and targeted treatment options. In this article, we will explore the attributes of BRCA and HER2, shedding light on their impact on cancer and the implications for patients.


The BRCA gene, short for Breast Cancer gene, refers to a pair of genes known as BRCA1 and BRCA2. These genes produce proteins that help suppress the growth of tumors and repair damaged DNA. Mutations in the BRCA genes can significantly increase the risk of developing breast, ovarian, and other types of cancer. Inherited mutations in BRCA1 and BRCA2 are responsible for the majority of hereditary breast and ovarian cancers.

Individuals with BRCA mutations have a lifetime risk of up to 80% for breast cancer and up to 40% for ovarian cancer. These risks are significantly higher compared to the general population. BRCA mutations can be detected through genetic testing, allowing individuals to make informed decisions about their healthcare and potentially take preventive measures.

Targeted therapies, such as PARP inhibitors, have been developed specifically for individuals with BRCA mutations. These drugs work by blocking the PARP enzyme, which cancer cells with BRCA mutations rely on for DNA repair. By inhibiting PARP, these drugs can selectively kill cancer cells while sparing healthy cells. This targeted approach has shown promising results in the treatment of BRCA-related cancers.

HER2 Gene

The HER2 gene, also known as Human Epidermal Growth Factor Receptor 2, is a gene that provides instructions for making HER2 proteins. These proteins are receptors found on the surface of cells and play a crucial role in cell growth and division. In normal cells, HER2 proteins help regulate cell growth, but when the HER2 gene is amplified or overexpressed, it can lead to uncontrolled cell growth and the development of certain types of cancer, including breast and gastric cancer.

Approximately 20% of breast cancers are HER2-positive, meaning they have an overexpression or amplification of the HER2 gene. HER2-positive breast cancers tend to be more aggressive and have a higher risk of recurrence compared to HER2-negative breast cancers. However, the development of targeted therapies has revolutionized the treatment of HER2-positive breast cancer.

HER2-targeted therapies, such as trastuzumab (Herceptin) and pertuzumab (Perjeta), work by specifically targeting the HER2 protein and inhibiting its signaling pathway. By blocking the HER2 protein, these drugs can slow down or stop the growth of cancer cells. These targeted therapies have significantly improved the prognosis and survival rates for patients with HER2-positive breast cancer.


BRCA mutations are relatively rare in the general population, occurring in approximately 1 in 400 individuals. However, the prevalence of BRCA mutations varies among different populations and ethnicities. For example, individuals of Ashkenazi Jewish descent have a higher prevalence of BRCA mutations, with about 1 in 40 individuals carrying a BRCA mutation.

On the other hand, HER2 overexpression or amplification is more common, occurring in approximately 20% of breast cancers. This makes HER2-positive breast cancer a significant subtype of the disease. The prevalence of HER2 overexpression in gastric cancer is also notable, with around 10-20% of gastric cancers being HER2-positive.

It is important to note that while BRCA mutations and HER2 overexpression are associated with increased cancer risk, not all individuals with these genetic alterations will develop cancer. Other factors, such as lifestyle, environmental exposures, and additional genetic variations, can influence the likelihood of cancer development.

Treatment Options

As mentioned earlier, targeted therapies have been developed for both BRCA-related cancers and HER2-positive cancers. For individuals with BRCA mutations, PARP inhibitors, such as olaparib (Lynparza) and rucaparib (Rubraca), have shown efficacy in the treatment of ovarian and breast cancers. These drugs are often used in patients who have already received other treatments or as maintenance therapy to prevent cancer recurrence.

For HER2-positive breast cancer, a combination of HER2-targeted therapies, chemotherapy, and hormone therapy is commonly used. Trastuzumab, pertuzumab, and ado-trastuzumab emtansine (T-DM1) are examples of HER2-targeted drugs used in the treatment of HER2-positive breast cancer. These drugs can be administered alone or in combination, depending on the stage and characteristics of the cancer.

It is worth noting that the development of resistance to targeted therapies can occur over time. Therefore, ongoing research is focused on understanding the mechanisms of resistance and developing new treatment strategies to overcome this challenge.


BRCA and HER2 are two genes that have significant implications in cancer development and treatment. While BRCA mutations are associated with an increased risk of breast and ovarian cancers, HER2 overexpression or amplification is linked to more aggressive forms of breast and gastric cancers. Both genetic alterations have led to the development of targeted therapies that have improved patient outcomes.

Genetic testing plays a crucial role in identifying individuals with BRCA mutations, allowing for proactive healthcare decisions and preventive measures. Similarly, HER2 testing helps determine the appropriate treatment approach for patients with HER2-positive breast or gastric cancer.

As research continues to advance, further understanding of the BRCA and HER2 genes will likely lead to more effective treatments and improved outcomes for patients with these genetic alterations. The future holds promise for personalized medicine, where genetic information will guide treatment decisions, ultimately leading to better patient care and outcomes.

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