The 4 key genes consist of ALOX5AP, HLA-DMB, HLA-DRA and SPINT2. ALOX5AP, also called 5-LO-activating protein (FLAP), which plays an important role in synthesis of leukotriene and associates with prognosis of primary neuroblastoma patients and esophageal squamous cell carcinoma patients [28]. The gene discussed is HLA-DRA; the disease is esophageal squamous cell carcinoma.