In addition, Jung et al. found that DNMT1-targeted inhibition by siRNA induced the re-expression and reversed DNA methylation including RASSF1A etc., and could also inhibit cell proliferation in the cancer cells in vitro with no DNA damage, but 5-Aza-CdR showed more cytotoxicity than siRNA-DNMT1 with significant DNA damage, which was harm to the normal cells [18]. This evidence concerns the gene DNMT1 and cancer.