DACT1 and esophageal cancer: Up-regulation of DACT1 and DACT2 but not DACT3 after treatment with 5-Aza-Dc, inferring that DNA methylation may be the main regulatory mechanism for the inactivation of DACT1 and DACT2 but not DACT3 in esophageal cancer cell lines, which further confirmed by direct BGS and MSP analysis of promoter methylation status of DACT1, 2, 3.