HER2 amplification refers to the overexpression or increase in the number of copies of the HER2 gene (Human Epidermal Growth Factor Receptor 2) in cancer cells. This gene plays a critical role in the regulation of cell growth, survival, and differentiation. HER2 is a member of the EGFR family of receptor tyrosine kinases, and its amplification can lead to uncontrolled cell proliferation, a hallmark of cancer.
