SOX2 and esophageal cancer: The peptide aptamer P42 possesses a constrained peptide expression cassette in the active site loop of thioredoxin and a partial fragment of Venus protein, which is capable of efficiently interacting with SOX2 and inhibiting SOX2 downstream genes.257 It has been recently demonstrated that P42 can effectively reduce SOX2 function and apparently decrease the proliferation and migration of human esophageal cancer cells both in vitro and in vivo.257,258