What causes HER2 gene amplification?

In about 25 percent of breast cancers, the cancer cells have an excess of the HER2 protein. This is caused by a mutation in the HER2 (human epidermal growth factor receptor 2) gene. When the HER2 gene mutates, it causes cells in the breast to grow and divide at an uncontrolled rate, leading to tumor growth.

What is HER2 gene amplification?

Amplification of the HER2 gene is the primary mechanism of HER2 overexpression in tumors1. HER2 amplification occurs before HER2 protein overexpression and monitoring of the tumor HER2 gene amplification status has therefore become routine in breast cancer2,3,4 surveillance.

How does HER2 amplification promote cancer?

However, amplification of the HER2 gene leads to overexpression of the receptor, which is linked to the development of many types of human cancers including breast, ovarian and those of the gastrointestinal tract [4, 5]. Breast cancer is a leading cause of cancer-related death in women.

How is the HER2 pathway activated?

HER2 can also be activated by complexing with other membrane receptors such as insulin-like growth factor receptor 1 [12]. Figure 1 [13] shows the main transduction pathways regulated by the four HER family members—EGFR, HER2, HER3, and HER4.

What is the normal function of HER2?

HER2 proteins are receptors on breast cells. Normally, HER2 receptors help control how a healthy breast cell grows, divides, and repairs itself. But in about 10% to 20% of breast cancers, the HER2 gene doesn’t work correctly and makes too many copies of itself (known as HER2 gene amplification).

Can HER2-positive become negative?

Research has shown that some breast cancers that are HER2-positive can become HER2-negative over time.

What causes HER2 positive cancer?

HER2-positive breast cancer is one form of breast cancer. Characterized by aggressive growth and a poor prognosis, it is caused by the overexpression of a gene called HER2 in tumor cells.

Is HER2-positive breast cancer hereditary?

HER2-positive breast cancer is not hereditary, but some other types of gene mutations related to breast cancer are inherited. Genetic testing can tell you if you have any of the mutations currently known to increase risk for breast cancer or other cancers.

What is the HER2 gene?

The human HER2 gene with the generic name ERBB2 (also known as NEU) encodes the HER2 protein or p185HER2. The HER2 protein is a membrane receptor tyrosine kinase with homology to the epidermal growth factor receptor ( EGFR ).

What is HER2 negative?

If breast cancer cells don’t have abnormal levels of HER2 proteins, then the breast cancer is considered HER2-negative. If your cancer is HER2-negative, it may still be estrogen- or progesterone-positive. Whether or not it is affects your treatment options.