Downregulation of retinoic acid receptor-β2 expression is linked to aberrant methylation in esophageal squamous cell carcinoma cell lines

Figure 1 RARβ2 expression and methylation in ESCC cell lines. A: RT-PCR analysis of RAR β2 expression, GAPDH was used as internal control. B: MSP analysis of RAR β2 promoter methyla-tion status, (U) lanes and (M) lanes represent amplification of unmethylated and methylated alleles, respectively. In vitro methylated DNA (IVD) and normal human peripheral lym-phocytes (NL) serve as positive and negative methylation controls, respectively.