Genetic predisposition of HER2-positive breast cancer: Understanding its origins and detection methods
Breast cancer can be a complex disease, with various genetic factors playing a significant role in its development. In this article, we delve into the world of inherited breast cancer, focusing on the key genetic mutations that increase the risk of this disease.
Approximately 5-10% of all breast cancers are caused by inheritable gene mutations, with the most common cause being mutations in the BRCA1 and BRCA2 genes. These genes are crucial for repairing DNA double-strand breaks, and mutations in them lead to a condition known as homologous recombination deficiency (HRD), which predisposes cells to malignant transformation.
People with BRCA1 or BRCA2 gene mutations face a significantly higher risk of developing breast cancer. By the age of 80, those with BRCA1 or BRCA2 mutations have a 7 in 10 chance of developing breast cancer, compared to about 12% in the general population. BRCA1-associated breast cancers tend to be aggressive, often triple-negative, while BRCA2-related cancers are more commonly hormone receptor-positive.
In addition to BRCA1 and BRCA2, other gene mutations, such as PALB2, TP53, CDH1, STK11, and PTEN, can also cause inherited breast cancer. PALB2 works in concert with BRCA2 in DNA repair, and mutations greatly increase breast cancer risk. TP53 is a tumor suppressor gene, and mutations can lead to Li-Fraumeni syndrome, a condition associated with increased breast cancer risk. CDH1 is linked to hereditary diffuse gastric cancer but also associated with lobular breast cancer risk, while STK11 causes Peutz-Jeghers syndrome, a condition associated with elevated breast cancer risk. PTEN mutations cause PTEN Hamartoma Tumor Syndrome (PHTS), which is also associated with breast cancer.
When it comes to diagnosing HER2-positive breast cancer, doctors may use immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) tests. IHC involves taking a breast tissue sample and staining the HER2 proteins with dye, with scores of 0-1 indicating HER2-negative, 2 indicating borderline, and 3 indicating HER2-positive. FISH involves attaching labels to HER2 proteins that change color and glow in the dark when they attach to HER2 proteins, and it returns a binary, positive or negative, test result.
It's important to note that the HER2 gene mutation is not hereditary. However, HER2-positive breast tumors usually grow faster and have a higher risk of spreading and recurring than HER2-negative breast tumors.
Preventing breast cancer involves maintaining a healthy lifestyle. People can reduce their risk by maintaining a healthy body weight, getting regular exercise, limiting or avoiding alcohol, breastfeeding if possible, and discussing any necessary hormone replacement therapy or birth control pills with their doctor.
For those with a family history of breast cancer or inherited mutations in the BRCA1 and BRCA2 genes, it's essential to talk with their doctor about additional ways to reduce their risk. Genetic testing can identify carriers and guide risk-reduction strategies and early interventions.
In conclusion, understanding the role of genetic mutations in breast cancer is crucial for early detection and prevention. By being aware of the key genetic factors, individuals can make informed decisions about their health and take proactive steps to reduce their risk.
- The BRCA1 and BRCA2 genes, when mutated, can lead to a negative predisposition for developing breast cancer, particularly triple-negative breast cancers, which are more aggressive.
- Other gene mutations, such as PALB2, TP53, CDH1, STK11, and PTEN, also contribute to inherited breast cancer, increasing the risk of various medical-conditions and cancers like gastric and lobular breast cancers.
- Despite the HER2 gene mutation not being hereditary, HER2-positive breast tumors grow faster, have a higher risk of spreading, and recurring, so regular health-and-wellness screenings could be vital for early detection and intervention.
