Upregulated miR‑203a‑3p and its potential molecular mechanism in breast cancer: A study based on bioinformatics analyses and a comprehensive meta‑analysis.

Breast cancer (BC) has been identified as the leading malignancy in women worldwide. However, the potential molecular mechanism of microRNA (miR)‑203a‑3p in BC remains to be elucidated. The present study evaluated the expression of miR‑203a‑3p in BC and adjacent normal tissue in several publically available datasets. The distinguishability of precursor miR‑203a and miR‑203a‑3p in BC tissue and adjacent breast tissue was assessed using receiver operating characteristic (ROC) and summarized ROC (sROC) approaches. In addition, gene ontology (GO) enrichment, Kyoto Encyclopedia of Genes and Genomes pathway analysis and protein‑protein interaction analysis were performed to determine the potential molecular mechanism of miR‑203a‑3p in BC. It was identified that the expression of precursor miR‑203a was markedly upregulated in 1,077 BC tissue samples compared to 104 adjacent breast tissue samples from The Cancer Genome Atlas. Additionally, an increasing trend in miR‑203a‑3p expression was observed in 756 BC tissue samples compared with 76 adjacent breast tissue samples from the University of California Santa Cruz Xena project. In addition, a comprehensive meta‑analysis suggested that the expression of miR‑203a‑3p was markedly increased in 2,444 BC tissue samples compared with 559 adjacent breast tissue samples. The area under the curve of the ROC and sROC revealed that miR‑203a‑3p expression was able to distinguish between BC tissue and adjacent breast tissue. However, miR‑203a‑3p exhibited no prognostic value in BC. The results of GO enrichment demonstrated that the miR‑203a target genes were associated with 'plasma membrane integrity', 'cell surface receptor linked signal and transduction' and '3',5'‑cyclic nucleotide phosphodiesterase activity'. 'Purine metabolism' was identified as the pathway with the most enrichment of miR‑203a‑3p target genes in BC. The present study also identified insulin‑like growth factor receptor (IGF1) as a hub gene associated with miR‑203a in BC. In summary, miR‑203a‑3p may enhance the development and oncogenesis of BC, and IGF1 was defined as a hub gene of miR‑203a‑3p in BC.