Hypermethylation of Long Non-Coding RNA Genes Group in the Breast Cancer Development and Progression.

We analyzed changes in the level of methylation of CpG islands in four long non-coding RNA (lncRNA) genes MEG3, ZNF667-AS1, GAS5, and SEMA3B-AS1 as promising markers of breast cancer. Methylation analysis was performed by quantitative methylation-specific PCR on a set of 38 paired (tumor/normal) breast cancer samples. Significantly (p<0.001) increased methylation was shown for three of the four lncRNA genes: MEG3, ZNF667-AS1, and SEMA3B-AS1. We found significant correlations of the methylation level of all the studied lncRNA genes with the stage of cancer and with lymphogenic metastasis, and for MEG3 and ZNF667-AS1 also with the tumor size. Methylation of ZNF667-AS1, and SEMA3B-AS1 genes in breast cancer was detected for the first time. Based on these findings, new potential markers for the diagnosis and prognosis of breast cancer can be proposed.