Importantly, genetic/epigenetic disruptions or altered expression levels of some TSG candidates mentioned above, including SMAD2, SMAD4, DCC, DLC1 and PARD3, have been reported in ESCC tumors and cell lines, indicating that aCGH study using multiple tumor cell lines could facilitate the identification of critical cancer genes in human tumors. The gene discussed is SMAD2; the disease is esophageal squamous cell carcinoma.