DRD4 and esophageal squamous cell carcinoma: Similarly, they identified ALOX12, ALOX12B, ANGPTL7, DRD4, MAPK9, SLC38A1, and ZNF419 as prognostic FRGs in patients with ESCC, among which the expression of ALOX12, ANGPTL7, DRD4 and MAPK9 in ESCC was significantly decreased.