Migration/invasion of tumor cell lines (CDKN2A, CST6, DPP4, KITLG, LAMA3, LCK, MDK, SERPINB5, TFF2, TGFA), tumorigenesis of intestinal polyp (ASPH), proliferation of tumor cell lines (APRIN, CDKN2A, CST6, IMP3, LITLG, PIWIL1, SLP1, TGFA), cytotoxic reaction (CDKN2A, LCK), invasion of tumor cell lines (CDKN2A, CST6, DPP4, SERPINB5, TFF2, TGFA), tumorigenesis of small intestine (PLA2G4A), size/tumorigenesis of polyp (ASPH, CDKN2A, TGFA). The gene discussed is PIWIL1; the disease is intestinal polyp.