Background: Circular RNAs (circRNAs) are important in tumorigenesis and cancer progression, highlighting their potential as biomarkers for diagnosis, prognosis, and treatment monitoring.

Methods: This study consists of experimental and in silico phases. In the experimental phase, the expression of hsa_circ_0052112 in tumor and blood samples from 40 breast cancer women was analyzed, compared to the control group using Sybr Green real-time RT-PCR followed by total RNA extraction and cDNA synthesis. Statistical analysis was performed using the beta-actin gene as a normalizer, compared to the normal control group as a fold change. In the in silico phase, interactions among circRNA, RNA-Binding Proteins (RBPs), and microRNAs (miRNAs) were investigated using Interactome Database. The miRcancer database was utilized to assess breast cancer-related miRNAs linked to hsa_circ_0052112. Target miRNAs were identified with TargetScan and filtered for relevance through DisGeNET. K-means clustering grouped genes by expression patterns, visualized in Cytoscape to illustrate circRNA-miRNA-mRNA relationships. Hub genes underwent pathway enrichment analysis using Reactome database to determine their functional significance.

Results: Data revealed a significant increase in hsa_circ_0052112 expression in both blood and tumour of breast cancer patients. This increase was especially pronounced in patients with estrogen, progesterone, and HER2 receptor positivity, as well as in advanced disease stages with lymph node involvement. Enrichment analysis of hub genes indicates their role in the PI3K/AKT signaling pathway.

Conclusion: hsa_circ_0052112 shows promise as a multifaceted biomarker for breast cancer, enhancing diagnosis and prognosis; while supporting personalized treatment strategies. Further clinical validation is necessary to confirm its utility.