DKK1 and gastric cancer: We identified a five-gene signature, including CPZ, Collagen Triple Helix Repeat Containing-1 (CTHRC1), Dickkopf-1 (DKK1), Epidermal Growth Factor (EGF), and Glypican Proteoglycan-3 (GPC3), with risk scores predictive of the prognosis of GC patients.