Long non-coding RNA (LncRNA) H19, one of the most intriguing non-coding RNAs, has been shown to play a key role in the development and therapy resistance of various digestive system cancers (including hepatocellular carcinoma, colorectal cancer, pancreatic ductal adenocarcinoma, esophageal carcinoma, gastric cancer, and biliary system cancer) by regulating the abnormal expression of genes. The gene discussed is H19; the disease is pancreatic ductal adenocarcinoma.