1 Oncology, Herlev and Gentofte Hospital, The Capital Region of Denmark2 Pathology, Herlev and Gentofte Hospital, The Capital Region of Denmark3 Breast Surgery, Herlev and Gentofte Hospital, The Capital Region of Denmark4 unknown
PURPOSE: Therapeutic decisions in breast cancer are increasingly guided by prognostic and predictive biomarkers. Non-protein-coding microRNAs (miRNAs) have recently been found to be deregulated in breast cancers and, in addition, to be correlated with several clinico-pathological features. One of the most consistently up-regulated miRNAs is miR-21. Here, we specifically searched for differentially expressed miRNAs in high-risk breast cancer patients as compared to low-risk breast cancer patients. In the same patients, we also compared miR-21 expression with the expression of its presumed target PTEN. METHODS: Both microarray and RT-qPCR techniques were used to assess miRNA expression levels in lymph node-positive and -negative human invasive ductal carcinoma tissues. Simultaneously, PTEN protein expression levels were assessed using immunohistochemistry. RESULTS: miR-486-5p and miR-139-5p were found to be down-regulated in patients with lymph node metastases, whereas miR-21 was found to be up-regulated in patients with a positive lymph node status. miR-21 expression levels were found to significantly correlate with tumour size (r = 0.403, p = 0.009; Spearman's rank), whereas no relation was found between miR-21 and PTEN expression levels (Kruskal-Wallis test). CONCLUSION: Down-regulation of miR-486-5p and miR-139-5p, in conjunction with up-regulation of miR-21, may represent a useful signature for the identification of high-risk breast cancer patients.
Cellular Oncology (dordrecht), 2014, Vol 37, Issue 3, p. 215-27