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. This evidence concerns the gene SMAD4 and esophageal squamous cell carcinoma.