['To study the role of hypermethylation in the loss of retinoic acid receptor beta(2) (RARbeta(2)) in esophageal squamous cell carcinoma (ESCC).', 'The role of hypermethylation in RARbeta(2) gene silencing in 6 ESCC cell lines was determined by methylation-specific PCR (MSP), and its methylation status was compared with RARbeta(2) mRNA expression by RT-PCR. The MSP results were confirmed by bisulfite sequencing of RARbeta(2) promoter regions.', "Methylation was detected in 4 of the 6 cell lines, and the expression of RARbeta(2) was markedly downregulated in 3 of the 4 methylated cell lines. The expression of RARbeta(2) was restored in one RARbeta(2) -downregulated cell line with the partial demethylation of promoter region of RARbeta(2) after 5-aza-2'-deoxycytidine (5-aza-dc) treatment."] Is downregulation of retinoic acid receptor-beta ( 2 ) expression linked to aberrant methylation in esophageal squamous cell carcinoma cell lines?