HER2 contributes to cancer in a manner similar to EGFR. When the HER2 gene is amplified, it leads to the overproduction of the HER2 protein on the cell surface. This can result in increased signaling for cell growth and division. In breast cancer, about 15-20% of cases are HER2-positive, and these cases are often more aggressive. HER2 status is an important factor in determining the treatment plan for breast cancer patients.
