Similar to PTEN, the 270 target genes obtained by method 1 are all negatively regulated by multiple miRNAs, and construct a huge regulatory network in digestive system tumors, affecting the proliferation, invasion, migration, and other malignant phenotype of gastric cancer, hepatocellular carcinoma, and colorectal cancer, and pancreatic cancer. This evidence concerns the gene PTEN and familial pancreatic carcinoma.