The results clearly showed that 99mTc-MIRC208, 99mTc-MIRC213 and 99mTc-MIRC220 are all able to bind specifically to HER2 ECD and the HER2-expressing 7HER2 BC cells rather than the other receptors in the HER family, murine HER2 ECD and HER2-low MCF-7 cells (Figure 2C-D and Figure S4). This evidence concerns the gene ERBB2 and breast cancer.