Abstract:To study the association between expression of DBC2 gene and itspromotermethylation,and the effect of DBC2 on the proliferation and apoptosis ofbreastcancer T-47D cells.M ethods Three breast cancercelllines(T-47D,MCF-7 and MDA-MB-23)and normalbreastcellline(MCF-10)were cultured ,the expression and promotermethylation status of DBC2 in the fourcelllines were measured.T-47D cells were treated by 5-Aza-CdR,and the effectof5-Aza-CdR on the DBC2 mRNA leveland promotermethylation status were detected.T-47D cellproliferation and apoptosis were determined by MTT and Annexin-V/PI respectively.Result DBC2 geneexpression wasnotobserved,whereas DBC2 promotermethylation wasfound in T-47D cells.5Aza-CdR reversed the methylation of DBC2 promoterand activated the expression of DBC2( < 0.05).The cell proliferation wassignificantly inhibited and the apoptosiswaspromoted in T-47D cellsaftertreatmentwith 5-Aza-CdR ( < 0.05). Conclusions The methylation of DBC2 promoter induces the silence of DBC2 mRNA. The activation of DBC2 geneexpression can inhibitthecellproliferation and promoteapoptosisofT-47D cell.