Thus far, only a few downstream targets of GLI1 have been identified. Recently, it was reported to be involved in PC invasion and metastasis, and has become a new target for treatment. However, little was known about the actual mechanism implied in its promotion of invasion and metastasis in PC. Moreover, we focused on accumulating evidence which demonstrated that carcinoma in various organs, including pancreas, is associated with aberrant DNA methylation, in which DNMTs is the key catalyst significantly correlated with accumulation of methylation of tumor-related genes, among which some were associated withcell proliferation such as APC, some were related with the reparation of DNA damage such as hMLH1, some were invasionor metastasis-related, such as TIMP-3, SPARK, and CDH1, or cell EX 527 death-related such as DAPK-1, thus playing an important role in multistage carcinogenesis of the pancreas from early precancerous stages to malignant progression. Recently, it was found that tumor burden is significantly reduced with decreasing DNMT1 levels in vivo, suggesting that DNMTs mediated DNA methylation is involved in pancreatic carcinogenesis. Based on this study and previous reports above, it’s possible that GLI1- DNMTs cascade help to invasion or metastasis through promoting the methylation of some invasion- or metastasis-related genes, and may facilitate tumor growth by promoting the methylation of some cell death-related genes. Our study showed that DNMT3a expression is regulated by GLI1 in human pancreatic cancer. However, the actual mechanism in the regulation of DNMT3a by GLI1 is still unknown. Recent years, many manuscripts have been reported that some microRNA families could target DNMTs in a diversity of human cancers. On the other hand, it was reported that some microRNA such as microRNA-29 family was transcriptional suppressed by c-Myc, hedgehog and NF-kappaB. Based on the evidence above, it is possible that Hh-GLI might regulate DNMT3a through some certain microRNAs, which remains to be explored. In our study, ChIP assays showed GLI1 bind to DNMT1 but not DNMT3a. We also noticed that GLI1 elevated DNMT3a more folds than DNMT1. We thought there were some possible underlying mechanisms as follows: First, GLI1 might not regulate DNMT3a directly but through a certain gene, which might be a kinase or activin, and via cascade amplification so as to lead a higher regulative efficiency of DNMT3a by GLI1. Second, Hedghog-GLI1 might directly or indirectly regulate several genes involved in different signaling pathways, and two or more of these genes also regulate DNMT3a and have synergetic effects, so that despite GLI1 might not regulate DNMT3a directly, but would elevate DNMT3a more folds when it over-expresses. To solve this question, it’s necessary to explore more target genes of Hedgehog-GLI1, and to probe into the crosstalk between various signaling pathways.