ERBB2 and breast cancer: Breast cancer is generally considered as noninflamed, and patients with breast cancer have responded poorly to therapy with checkpoint blockade antibodies.[36, 37] To test whether a μGCVax could also stimulate antitumor immune response in breast cancer, we prepared a breast cancer‐specific vaccine by replacing Trp2 peptide with Her2p66 (μGCHer2) which is a class I Her2 peptide.[25, 38] BALB/c mice with primary Her2‐positive TUBO tumors were treated with μGCHer2, and tumor infiltration of T cells was analyzed (Figure 3a).