The primary objectives of this study (ClinicalTrials.gov Identifier: NCT05412446) were the evaluation of uptake of [99mTc]Tc-ADAPT6 (SUV) and lesion-to-background ratios for primary tumours and metastatic lymph nodes in patients with HER2-positive and HER2-negative breast cancer. This evidence concerns the gene ERBB2 and neoplasm.