Phase I clinical trials conducted at the Department of Radionuclide Therapy andDiagnostics of CRI TNRMC on HER2/neu in BC patients using a number ofdiagnostic radiopharmaceuticals ([99mTc]Tc-(HE)3-G3,[99mTc]Tc-ADAPT6, and 99mTc-ZHER2:41071) [13, 14, 18] have demonstrated not only the safecharacter of the procedure, but also the possibility of typing primary breasttumors depending on their HER2/neu status (p < 0.05,Mann– Whitney test) [21]. The gene discussed is ERBB2; the disease is breast cancer.