In fact, this same group developed a functionalized PAMAM, with a multi-targeted nanosystem using anti-HER2 VHH (deriving from single chain variable library) coupled to CXCR1 promoter, PE38 toxin A gene and bFGF 5′UTR which selectively caused cytotoxicity in HER2-positive Breast Cancer Stem Cells. The gene discussed is CXCR1; the disease is breast cancer.