Two potential regulatory axes in breast cancer patients: hsa_circ_0001546/hsa-miR-532-5p/ZFHX3 and hsa_circ_0025244/hsa-miR-210-5p/BTG2

Purpose: This study aims to investigate the expression profiles of hsa_circ_0025244 and hsa_circ_0001546 in breast tissue samples and to propose potential regulatory axes for these circular RNAs. Materials and Methods: The expression levels of hsa_circ_0025244 and hsa_circ_0001546 were determined in 55 tumor tissue samples (30 Luminal B and 25 Luminal A) and 55 adjacent normal tissue samples using quantitative polymerase chain reaction. Subsequently, in silico databases and PubMed literature searches were employed to identify potential sponge microRNAs and target genes. Finally, potential regulatory axes were proposed for further investigation in breast cancer. Results: Both hsa_circ_0025244 and hsa_circ_0001546 were downregulated in total tumor tissues and Luminal B tumor tissues compared to normal tissues. However, only hsa_circ_0025244 was downregulated in Luminal A tumors compared to normal tissues. According to in silico tools and PubMed searches, the strongest target microRNA/gene association was determined to be hsa-miR-210-5p/BTG2 for hsa_circ_0025244 and hsa-miR-532-5p/ZFHX3 for hsa_circ_0001546. Conclusion: This study demonstrates that, hsa_circ_0025244 and hsa_circ_0001546, investigated for the first time in breast cancer, were found to exhibit decreased expression in breast cancer compared to normal tissue samples.