ERBB2

The ERBB2 gene is also commonly referred to as Her-2/neu, especially by doctors and other clinicians. This gene is one member of a family of genes that provide instructions for producing growth factor receptors. Growth factors are proteins that stimulate cell growth and division.

The ERBB2 gene provides instructions for making a protein called the ErbB2 growth factor receptor. This receptor is located on the surface of cells, where it associates with similar receptors to form a complex. Growth factors bind to these similar receptors (ErbB3, for example) and trigger the receptor complex to relay signals inside the cell. These signals activate certain genes that promote cell growth. ErbB2 probably also plays a role in connecting cells together (cell adhesion), the process by which cells mature to carry out specific functions (cell specialization), and cell movement.

breast cancer - associated with the ERBB2 gene

Some gene mutations are acquired during a person's lifetime and are present only in certain cells. These changes, which are called somatic mutations, are not inherited. Somatic mutations sometimes occur when DNA makes a copy of itself (replicates) in preparation for cell division. Errors in the replication process can result in multiple copies of a gene on a chromosome. The presence of multiple gene copies, known as gene amplification, can underlie the formation and growth of tumor cells depending on which gene is amplified. For example, amplification of the ERBB2 gene is found in about 25 percent of breast cancers. Extra copies of this gene cause too much of the ErbB2 receptor protein to be made in the cell (overexpression). Excess ErbB2 protein signals cells to grow and divide continuously, which can contribute to the growth of cancerous tumors. Overexpression of ErbB2 is associated with aggressive breast tumors that are more likely to spread to other tissues (metastasize).

other cancers - associated with the ERBB2 gene

Amplification of the ERBB2 gene has been reported in several other types of cancer, including ovarian, brain, stomach, and lung cancers. ERBB2 amplification results in overproduction of the ErbB2 protein, which likely stimulates cells to grow and divide continuously. This uncontrolled cell division can lead to the growth and progression of cancerous tumors.