PTK7 and neoplasm: Up to now, aptamers have already been developed for various targets, such as thrombin [81], HBV virus [82], E. Coli [83] and other bacteria, aflatoxin [84,85], prostate specific antigen (PSA) [86], CEA tumor markers [87], or cell membrane proteins such as protein tyrosine kinase 7 (PTK7) in the CCRF-CEM T-lymphoblast membrane and others [88].