HER2 (Human Epidermal Growth Factor Receptor 2), also known as ERBB2, CD340, and 
Neu protooncogene, is a member of the epidermal growth factor receptor (EGRF) 
family. Members of the ERBB family, including HER2, activate molecular cascades 
that stimulate proliferation and migration of cancer cells, as well as their 
resistance to the anticancer therapy. These proteins are often overexpressed 
and/or mutated in various cancer types and represent promising targets for the 
anti-cancer therapy. Currently, anti-HER2 drugs have been approved for the 
treatment of several types of solid tumors. HER2-specific therapy includes 
monoclonal antibodies and low-molecular weight inhibitors of tyrosine kinase 
receptors, such as lapatinib, neratinib, and pyrotinib. In addition to the 
activation of molecular pathways responsible for cell proliferation and survival 
under stress conditions, HER2 directly regulates programmed cell death. Here, we 
review the studies focused on the involvement of HER2 in various signaling 
pathways and its role in the regulation of apoptosis.