Abstract 2391: Integrated analysis of methylation and expression profile of telomere-related genes in breast cancer patients

Abstract

Abstract Telomeres at the ends of chromosomes are critical in maintaining the integrity and stability of the genome. Aberrant telomere or telomerase dysfunction participates in tumorgenesis. A majority of human cancers exhibit critically aberrant telomere length, suggesting that tumors can arise from genetically instable cells with dysfunctional telomeres. Many genes are involved in the complex regulatory mechanisms of telomere length and telomerase activity. In addition, the methylation and expression pattern for most of telomere related genes in breast cancer are still unknown. Using microfluidic-PCR based target enrichment and next-generation bisulfite sequencing technology, we explored the promoter methylation profile of 29 telomere-related genes in 184 breast cancer patients with paired tumor and matched normal tissues. The average methylation level was significantly higher in tumor (8.13%) than that in matched normal tissues (7.08%) (P = 4.30E-21). Four genes showed significant hyper-methylation in the breast tumor tissues. All of these 4 genes are annotated with potential TFBSs in the promoter regions. In subtype analysis, RAD51D showed significant methylation difference among four subtypes. In analysis of the association between methylation and clinicopathologic characteristics, TERC showed significant difference between ER+/ER- tumors. The expression profile of the 4 significant hyper-methylated genes was explored in the same cohort using qPCR method. All of them showed significantly lower expression in breast tumor tissues compared with the matched normal tissues. Two genes showed significant and negative cis correlation between methylation and gene expression. These results were also validated in the TCGA database. The 4 genes panel showed a good performance in predicting breast cancer with ROC analysis. In summary, our results revealed the methylation pattern of telomere related genes in breast cancer and illustrated the epigenetic regulatory mechanism on expression of aberrant methylated genes. Our study provides a novel panel of telomere related genes which may be a valuable diagnostic biomarker for breast cancer prediction. Note: This abstract was not presented at the meeting. Citation Format: Jianfu Heng, Xinwu Guo, Lili Tang, Fan Zhang, Limin Peng, Ming Chen, Xipeng Luo, Xunxun Xu, Shouman Wang, Jun Wang. Integrated analysis of methylation and expression profile of telomere-related genes in breast cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2391. doi:10.1158/1538-7445.AM2017-2391