Comparison of microRNA expression levels between primary and recurrent breast cancer: MicroRNA-133a, microRNA-191, and microRNA-204 can predict local recurrence of breast cancer

Background: Identification of patients with the potential of local recurrence after resection of breast cancer can help achieve an optimal management. We evaluated microRNA (miRNA) expression as a predictable biomarker in primary breast cancers and corresponding breast cancers. Methods: MiRNA expression array was used to search candidate miRNAs between primary and recurrent breast cancer from 5 patients. These miRNAs were further verified by real-time RT-PCR in a cohort of 25 patients. Results: 8 miRNAs including miRNA-26a, miRNA-133a, miRNA-133b, miRNA-186, miRNA-191, miRNA-194, miRNA-204, miRNA-296-5p were selected as candidates in a miRNA expression array. 2 miRNAs (miRNA-133a and miRNA-191) showed significantly different expression level between primary and recurrent tumor in the validation cohort, with down-regulation of miRNA-133a and up-regulation of miRNA-191 were identified in recurrent tumor. The initial expression level of miRNAs was another potential biomarker. 2 miRNAs (miRNA-191 and miRNA-204) were significantly correlated with disease-free survival, with higher expression of miRNA-191 and lower expression of miRNA-204 revealed worse prognosis. Conclusions: We demonstrate that miRNA-133a, miRNA-191, and miRNA-204 can be useful biomarkers for predicting breast cancer recurrence. MiRNA-191 is supposed to be a potential oncogenic miRNA, and miRNA-133a and miRNA-204 are supposed to play as tumor suppressors in the process of breast cancer recurrence.