Xu Junnan, Jing Mingxi, Sun Tao

Department of Internal Oncology, Shenyang LiaoningCancer Hospital & Institute

Objective:An increasing number of studies havesuggested that the link between ERα methylation and triple-negative breastcancer (TNBC). We previously found the ERα methylation status in basal-likebreast cancer was significantly higher than that in sporadic non-basal-likebreast cancer. However, the associations of ERα methylation and drug resistantduring the therapy in TNBC remains unclear. Method: Methylation-specificpolymerase chain reaction was used to investigate the methylation of ERα ingenomic DNA of 35 patients with TNBC, who were analyzed cisplatin-basedchemotherapy resistant status by chemosensitivity testing. Result: Ofthe 35 TNBC analysed, eight cases showed ERα promoter DNA methylation and 12cases were cisplatin-based resistant, and there was strongly associated withERα methylation and cisplatin resistant. Cisplatin resistant was confirmed inunivariate and in pairwise multivariate analysis adjusting for age, grade,TP53, BRCA mutant and ERα promoter DNA methylation. Cisplatin resistant weregreatly associated with ERα methylation, younger women, higher tumor size andBRCA non-mutant. The results generated from tumor tissue and normal tissuerevealed that BRCA expression were overexpression in breast tumor tissue withERα methylation. Conclusion: ERα methylation was shown to be a strongand independent biomarker for outcome prediction and cisplatin-based resistantin TNBC.

Key Words: TNBC ERα methylation  cisplatin resistant