SELEX has tested a number of aptamers targeting tumor cells, for example, A10 aptamer (against prostate-specific membrane antigen; PSMA), AS1411 aptamer (against nucleolin) [58], EpCAM aptamer (against epithelial cell adhesion molecule), and Sgc8 aptamer (against protein tyrosine kinase 7; PTK7). The gene discussed is PTK7; the disease is neoplasm.