These QDs, when attached to human epidermal growth factor receptor 2 (HER2) antibodies, displayed two-photon imaging in HER2-overexpressed MCF7 cancer cells and xenograft breast tumors in mice.29 The multifunctional studies demonstrated by these fluorescence HQDs could be helpful in imaging and targeted cancer therapy.30 The gene discussed is ERBB2; the disease is breast neoplasm.