Abstract :
[en] Circulating microRNAs (miRNAs) have been extensively studied in cancer as biomarkers but
little is known regarding the influence of anti-cancer drugs on their expression levels. In this
article, we describe the modifications of circulating miRNAs profile after neoadjuvant
chemotherapy (NAC) for breast cancer. The expression of 188 circulating miRNAs was
assessed in the plasma of 25 patients before and after NAC by RT-qPCR. Two miRNAs, miR-
34a and miR-122, that were significantly increased after NAC, were measured in tumor tissue
before and after chemotherapy in 7 patients with pathological partial response (pPR) to NAC.
These 2 chemotherapy-induced miRNAs were further studied in the plasma of 22 patients
with adjuvant chemotherapy (AC) as well as in 12 patients who did not receive any
chemotherapy. Twenty-five plasma miRNAs were modified by NAC. Among these miRNAs,
miR-34a and miR-122 were highly upregulated, notably in pPR patients with aggressive
breast cancer. Furthermore, miR-34a level was elevated in the remaining tumor tissue after
NAC treatment. Studying the kinetics of circulating miR-34a and miR-122 expression during
NAC revealed that their levels were especially increased after anthracycline-based
chemotherapy. Comparisons of the plasma miRNA profiles after NAC and AC suggested that
chemotherapy-induced miRNAs originated from both tumoral and non-tumoral
compartments. This study is the first to demonstrate that NAC specifically induces miRNA
expression in plasma and tumor tissue, which might be involved in the anti-tumor effects of
chemotherapy in breast cancer patients.
Publisher :
Wiley Liss, Inc., New York, United States - New York
Name of the research project :
Circulating miRNAs as diagnostic, prognostic and predictive markers in breast cancer patients
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