REG1A and cancer: By comparing the tumor stem cells of six cancers, we extracted the core gene set that plays an important role in UGCSCs and explored the possible pathogenic pathway of UGIC and core genes including GAST, CXCL8, CXCL3, PIGR, REG1A, and TFF3. With further in-depth research, these genes can also be used as diagnostic markers or possible therapeutic targets for gastrointestinal cancers.