17P - Development of an exo-miRNA panel for metastasis prediction in breast cancer

Background

Emerging evidence shows that exosomal miRNAs (Exo-miRNAs) mediate crosstalk between breast cancer (BC) cells and the tumor microenvironment (TME), modulating cancer hallmarks. FDG-PET/CT is increasingly used for restaging and detecting distant metastasis in BC patients, but its high cost and radiation hazard limit its use, especially in resource-limited settings. Owing to their stability and functional activity, Exo-miRNAs are being explored as non-invasive alternative biomarkers in several cancers. This study aims to develop an Exo-miRNA panel as a complementary tool for predicting metastasis and staging BC patients.

Methods

We enrolled 78 BC patients referred for FDG-PET/CT between 03/2022 and 10/2023. FDG-PET/CT was used as the reference standard for staging and metastasis. Exo-miRNAs were profiled from plasma using next-generation sequencing. In the discovery phase, 18 patients were randomly selected and categorized into three groups: Early (stage I+II, n=6), Advanced localized (stage III, n=6), and Metastasis (stage IV, n=6). Differentially expressed Exo-miRNAs (DE-Exo-miRNAs) were identified using DESeq2 with a fold change cutoff of <1.5> and an adjusted p-value < 0.05 followed by qPCR validation.

Results

We identified 22 DE-Exo-miRNAs across the groups, including unique and common miRNAs. For Early vs. Advanced, hsa-miR-122-5p and hsa-miR-183-5p were upregulated, while hsa-miR-203a-3p was downregulated. In Early vs. Metastatic, hsa-miR-92a-2-3p and hsa-miR-320a-3p were upregulated, whereas hsa-let-7a-5p and hsa-miR-486-5p were downregulated. hsa-miR-22-3p, hsa-miR-23b-3p, and hsa-miR-146a-5p were uniquely upregulated, highlighting their potential for differentiating stage IV patients from I & II. For Advanced vs. Metastatic, hsa-miR-92a-2-3p, hsa-miR-320a-3p, and hsa-miR-100-5p continued upregulation, while hsa-miR-26b-5p, hsa-miR-7-5p, and hsa-miR-222-3p were downregulated in metastatic patients. Gene ontology and pathway analysis supported DE-Exo-miRNAs as important regulators of disease pathology.

Conclusions

Our findings highlight the potential of Exo-miRNAs as biomarkers for predicting progression and metastasis risk with advantages of lower cost and broader accessibility.

Editorial acknowledgement

Clinical trial identification

Legal entity responsible for the study

D.A. Khan.

Funding

Higher Education Commission (HEC) Pakistan (Grant ID# 20-16564).

Disclosure

All authors have declared no conflicts of interest.