Actin filament associated protein 1 antisense RNA 1 (AFAP1-AS1) is an antisense RNA gene encoding AFAP1, first identified in esophaguseal and Barrett tumor development, that may function as a potential biomarker to predict the clinical outcome of cancer patients including those with pancreatic ductal adenocarcinoma, esophageal squamous cell carcinoma, and gallbladder cancer [69, 70]. This evidence concerns the gene AFAP1 and esophageal squamous cell carcinoma.