ERBB2 and cancer: AS1411, an aptamer conjugated with nucleolin overexpressed on the surface of cancer cells, was attached to tFNA at one vertex, and was reported to improve the efficiency of cellular endocytosis to deliver therapeutic and imaged tFNA.58,59,106–109 Similarly, Ma et al. adopted an anti-HER2 aptamer carried by tFNAs to target HER2-positive breast cancer cells.