Published in:
01-06-2014 | Original Paper
Differential expression of miR-139, miR-486 and miR-21 in breast cancer patients sub-classified according to lymph node status
Authors:
Lene Rask, Eva Balslev, Rolf Søkilde, Estrid Høgdall, Henrik Flyger, Jens Eriksen, Thomas Litman
Published in:
Cellular Oncology
|
Issue 3/2014
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Abstract
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.