ROI analysis of [68Ga]P6 showed a positive but non-significant trend in tumor-to-muscle ratio after 1 h for the HER2-positive mice compared to the HER2-negative mice (1.37 ± 0.30 versus 1.20 ± 0.18; p = 0.36; n = 4). The gene discussed is ERBB2; the disease is neoplasm.