The tumour uptake of [99mTc]Tc-(HE)3-G3 was measured before the neoadjuvant therapy of HER2–positive breast cancer using the TCbHP regimen (combination of docetaxel, carboplatin, trastuzumab and pertuzumab) and after 2 and 4 cycles of such therapy. This evidence concerns the gene ERBB2 and breast carcinoma.