TFPI2 and Barrett esophagus: In recent years, esophageal sponge cytology combined with biomarkers, like TFF3 [16], tissue factor pathway inhibitor 2 (TFPI2) [18], vav guanine nucleotide exchange factor 3 (VAV3) [19], and microRNA [20], have been validated to have high efficiencies in detecting Barrett's esophagus and associated adenocarcinoma.