As a peptide-based cancer vaccine stimulating CD4 + T helper cells, AE37 exhibits potential in inducing memory cells in the immune system alongside CD8 + cytotoxic T cells, contributing to an effective immune response.[13,14] These T cells are essential for the body’s adaptive immune response to foreign bodies, pathogens, and tumors, holding promise in sometimes averting recurrence.[15] This review explores the current evidence on the AE37 HER2-targeted vaccine in treating breast cancer recurrence. This evidence concerns the gene ERBB2 and breast cancer.