Methods: Thirty-one patients with primary breast cancer were enrolled and divided into three cohorts (injected with 500, 1000, or 1500 μg ZHER2:41071) comprising at least five patients with high (positive) HER2 tumor expression (IHC score 3+ or 2+ and ISH positive) and five patients with low (IHC score 2+ or 1+ and ISH negative) or absent HER2 tumor expression. Here, ERBB2 is linked to breast cancer.