Using a previously FDA-approved HER2 IHC assay, we identified clinical breast cancer tissue samples with HER2 expression scores of 3+ (Figure 3A, B, C), 2+ (Figure 3D, E, F), 1+ (Figure 3G, H, I), and 0 (Figure 3J, K, L). This evidence concerns the gene ERBB2 and breast carcinoma.