The studies covered gastric cancer, colorectal cancer, cholangiocarcinoma, pancreatic adenocarcinoma (PAAD), hepatocellular carcinoma (HCC), esophageal squamous cell carcinoma (ESCC), and gallbladder carcinoma (GBC), and all used real-time fluorescent quantitative polymerase chain reaction (qRT-PCR) to detect of AFAP1-AS1. The gene discussed is AFAP1; the disease is esophageal squamous cell carcinoma.