Analysis of selected circulatory microRNAs in breast cancer before and after chemotherapy
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Date
2018-09
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Addis Ababa Universty
Abstract
reast cancer is the second most common cause of death from cancer in women.
There is now increased prevalence of breast cancer among African women. In
Ethiopia it is the leading cancer type constituting 33% of all cancer cases in
women. It is a heterogeneous type of disease which comprises of many
biologically different and pathologically distinct features that lead to different
treatment responses.
Tests and procedures for diagnosis and prognosis of breast cancer are still
limited to invasive procedures and imaging techniques. Based on their
differential expression in disease and with their exceptional stability in biological
fluids, microRNAs are noticeable candidates to be used as non-invasive
diagnostic and prognostic biomarker. The association of change in expression
level of microRNAs with clinicopathological parameters may demonstrate their
potential in sorting the heterogeneous disease to specific subgroups for effective
treatment options.
The purpose of this study was to investigate the differential expression of
specific circulatory microRNAs in breast cancer patients and study their
association with clinicopathological parameters with samples from healthy
volunteers serving as control. Changes in the level of microRNA after completing
chemotherapy was also assessed and checked for association with serum CA 15-3
values to see the prognostic potential of specific microRNAs.
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The levels of specific circulatory microRNAs in patient and control samples were
analyzed using qRT-PCR. Serum CA 15-3 values from patient samples collected
after completion of chemotherapy were measured using solid phase enzyme
linked immunosorbent assay.
In this study miRNA 21-5p was significantly over expressed in the serum of
breast cancer patients when compared with controls (P<0.05). Receiver operating
characteristic curve analysis shows its potential in differentiating breast cancer
patients from controls with AUC value of 0.6 (P<0.05). A significant decrease in
serum miR-326 was observed after chemotherapy (P<0.05) as compared to serum
samples collected before chemotherapy. No correlations was found between
serum CA 15-3 values and levels of circulatory microRNAs. Mean serum CA 15-3
value of patients with stage IV breast cancer was found to be high when
compared with patients with other stages (P<0.001). Well-designed studies are
required to elucidate the clinical validity of deregulated microRNAs in breast
cancer to be used as diagnostic and prognostic biomarkers. Since deregulated
miRNAs in the circulation are shared by several cancer types and subtypes,
further studies are necessary to identify a well characterized cluster of miRNAs
with discriminative ability.
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Keywords
Breast cancer,heterogeneous