ERBB2 and breast cancer: Rainone and his group developed multifunctional fluorescent 99mTc-labeled silica NP (SiNP) functionalized with anti-HER2 (Human Epidermal Growth Factor Receptor 2) antibody in the form of a Trastuzumab-half chain (Hc-TZ) for HER2-positive breast cancer detection through SPECT [46].