HER2 is an important biomarker and therapeutic target in several cancers. In breast cancer, for instance, approximately 20-30% of cases involve HER2 overexpression. This overexpression is associated with a more aggressive disease course and poorer prognosis. HER2 testing is crucial for the diagnosis and treatment planning of these cancers. Techniques such as immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) are commonly used to determine HER2 status in tumor tissues.
