“…All other chemicals were of analytical grade and were purchased from Wako Pure Chemicals (Osaka, Japan) and Sigma (St. Louis, MO, USA). The 20 KYSE human esophageal squamous cell carcinoma cell lines, (KYSE-30, -140, -150, -170, -180, -200, -220, -350, -410, -450, -510, -520, -590, -770, -850, -890, -1170, -1190, -1250, and -2270) were prepared as previously described (12). All cell lines were cultured in RPMI-1640 medium (Life Technologies, Inc., Grand Island, NY) containing 10% heat-inactivated fetal bovine serum (FBS; BioWhittaker, Verviers, Belgium) at 37ËC in a humidified atmosphere of 5% CO 2 and maintained in continuous exponential growth by passage every 3 days.…”