ABSTRACT: A total of 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 kindly provided by Dr. Y. Shimada (Kyoto University, Kyoto, Japan). The KYSE 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) in a humidified atmosphere of 5% CO2 and maintained in continuous exponential growth by passage every 3 days. The exponentially growing cultured cells (2 x 10^6) were collected after two-washings with PBS. Total RNA was prepared from the frozen cell pellets using QIAGEN RNeasy mini kit (QIAGEN, Inc., Valencia, CA). The quality of the