Awareness of
breast cancer has been increasing due to early detection, but the advanced disease has limited treatment options. There has been growing evidence on the role of
miRNAs involved in regulating the resistance in several
cancers. We performed a comprehensive systematic review and meta-analysis on the role of
miRNAs in influencing the chemoresistance and sensitivity of
breast cancer. A bibliographic search was performed in PubMed and Science Direct based on the search strategy, and studies published until December 2018 were retrieved. The eligible studies were included based on the selection criteria, and a detailed systematic review and meta-analysis were performed based on
PRISMA guidelines. A random-effects model was utilised to evaluate the combined effect size of the obtained hazard ratio and 95% confidence intervals from the eligible studies. Publication bias was assessed with Cochran's Q test, I2 statistic, Orwin and Classic fail-safe N test, Begg and Mazumdar rank correlation test, Duval and Tweedie trim and fill calculation and the Egger's bias
indicator. A total of 4584 potential studies were screened. Of these, 85 articles were eligible for our systematic review and meta-analysis. In the 85 studies, 188 different
miRNAs were studied, of which 96 were upregulated, 87 were downregulated and 5 were not involved in regulation. Overall, 24 drugs were used for treatment, with
doxorubicin being prominently reported in 15 studies followed by
Paclitaxel in 11 studies, and 5 drugs were used in combinations. We found only two significant HR values from the studies (miR-125b and miR-4443) and our meta-analysis results yielded a combined HR value of 0.748 with a 95% confidence interval of 0.508-1.100; p-value of 0.140. In conclusion, our results suggest there are different
miRNAs involved in the regulation of chemoresistance through diverse
drug genetic targets. These
biomarkers play a crucial role in guiding the effective diagnostic and prognostic efficiency of
breast cancer. The screening of
miRNAs as a theragnostic
biomarker must be brought into regular practice for all diseases. We anticipate that our study serves as a reference in framing future studies and clinical trials for utilising
miRNAs and their respective
drug targets.