Expression and clinical significance of microRNA and its target gene EZH2 in breast cancer / 医学研究生学报

ABSTRACT

Objective Recently, the incidence of breast cancer has been the highest among female malignant tumors. Therefore, potential biomarkers are urgently needed to predict and prevent breast cancer. This study was aimed to explore the expression and clinical significance of differential miRNAs and their target genes in breast cancer by establishing miRNA expression profile in breast cancer tissues. Methods From January 2015 to December 2018, a total of 137 cases of breast cancer tissues with paired paracancerous tissues and 20 cases of breast fibroadenoma tissues were collected from the department of breast surgery, affiliated hospital of Guizhou Medical University. The tissues were divided into breast cancer group, paracancerous group, breast fibroadenoma group and lymph node metastasis group. High-throughput sequencing technique was used to detect the miRNAs in breast cancer tissues and paired paracancerous tissues. Real-time PCR verified the expressions of the three miRNAs with the most significant expression differences in different groups. Finally, bioinformatics analysis was used to predict the target genes and investigate the expression of miRNAs and proteins of target genes in different breast diseases. Results A total of 157 upregulated and 162 downregulated miRNAs were screened by high-throughput sequencing. Mir-hsa-miR-532-3p and hsa-miR-1260b were the most significant in upregulated miRNAs while has-let-7c-5p was the most significant in downregulated miRNAs. Meanwhile, bioinformatics analysis showed that their target gene was EZH2. Compared with para-cancerous group, expressions of hsa-miR-532-3p and hsa-miR-1260b were significantly upregulated while hsa-let-7c-5p was significantly down-regulated in breast cancer group and lymph node metastasis group (all P<0.05). The miRNA expressions of target gene EZH2 in breast cancer group, breast fibroadenoma group and lymph node metastasis group (1.24±0.01, 4.02±0.01, 15.97±0.01, respectively) were upregulated when compared with the para-cancerous group (1.00±0.00), and the similar conclusion could be drawn in EZH2 protein expression. Conclusion Hsa-miR-532-3p, hsa-miR-1260b and hsa-let-7c-5p were closely related to breast cancer, which may promote the occurrence and development of breast cancer by inducing the transcriptional expression of EZH2. HsamiR-532-3p, hsa-miR-1260b, hsa-let-7c-5p and EZH2 may be potential tumor biomarkers of breast cancer.