ERBB2 and cancer: TAAs differ from normal cellular proteins in their localization, levels of expression, or processing by the major histocompatibility complex (MHC), which allows for their effective targeting in tumors [24], and since the processing of the HER2 receptor will theoretically increase due to its overexpression, leading to an increase in the supply of HER2 peptides that can occupy a significant number of MHC molecules compared to other peptides, the HER2 antigen, therefore, can be effectively used as a target for cancer therapy [21].