In our study, the mRNA expressions of SNRPN, PEG10 and MEST were observed to decrease with advancing gestation in placental tissue and seemed to be regulated by increased methylation at their DMRs as well as H3K27me3 level and additionally increased H3K9me3 levels for MEST. Based on the importance of these genes in tumor growth, the observed high expression of these genes in early pregnancy suggests the possible role of these genes in high tumorous behavior associated with early gestational placenta. This evidence concerns the gene PEG10 and neoplasm.