As shown earlier (Fig. 1d and Fig. 2c), hypermethylation of the RARRES1 promoter was observed in choriocarcinoma cell lines and correlated with reduced gene expression and loss of transcriptional activation of RARRES1. In the light of these results we analyzed the RARRES1 expression in choriocarcinoma tissue (n = 10). This evidence concerns the gene RARRES1 and choriocarcinoma.