PTK7 and neoplasm: Up to now, aptamers have been developed for various targets such as thrombin, HBV virus, E. Coli, and other bacteria, aflatoxin B1 or M1, PSA, CEA tumor markers, or cell membrane proteins such as protein tyrosine kinase 7 (PTK7) in the CCRF-CEM T-lymphoblast membrane and others [134,135,136,137,138,139,140,141].