A systematic review and meta-analysis published in PLOS ONE found that circulating microRNAs and lipidomic/metabolomic biomarkers demonstrate strong aggregate diagnostic performance for breast cancer detection, yet substantial heterogeneity and reliance on retrospective case-control designs preclude near-term clinical deployment.
A newly published systematic review and meta-analysis in PLOS ONE evaluated the diagnostic accuracy of two emerging liquid biopsy modalities—circulating microRNAs (miRNAs) and lipidomic/metabolomic biomarkers—for early breast cancer detection. Pooled analyses indicated strong overall sensitivity and specificity across included studies, suggesting meaningful signal in both biomarker categories.
Despite favorable aggregate performance metrics, the authors identified considerable between-study heterogeneity as a central limitation. Most contributing studies employed retrospective case-control designs rather than prospective screening cohorts, a methodological distinction with direct implications for how these findings should be interpreted. Retrospective designs are prone to spectrum bias and do not replicate the real-world conditions under which a screening tool would be deployed.
The investigators also flagged potential small-study effects, raising concerns about publication bias inflating apparent diagnostic accuracy. Lack of harmonized pre-analytic protocols and inconsistent threshold definitions across studies further complicate cross-study comparisons. At this stage, both biomarker classes are characterized as investigational and complementary to—not substitutes for—standard mammographic screening.
The authors call for large-scale, prospective studies with standardized pre-analytic workflows and prespecified diagnostic cutoffs before these biomarkers can be meaningfully integrated into breast cancer screening or triage algorithms.
Key points
- Pooled data indicate strong diagnostic sensitivity and specificity for circulating miRNAs and lipidomic biomarkers in breast cancer detection.
- Substantial heterogeneity across included studies limits confidence in aggregate estimates.
- The majority of studies used retrospective case-control designs, not prospective screening cohorts, reducing real-world applicability.
- Potential small-study effects and publication bias may be inflating observed diagnostic accuracy.
- Both biomarker classes remain investigational; prospective, standardized validation studies are required before clinical implementation.
Why it matters
Oncologists and radiologists should be aware that while circulating miRNA and lipidomic biomarkers represent a scientifically compelling adjunct to mammography, current evidence does not support their use as standalone or replacement screening tools. Rigorous prospective validation is a prerequisite for any clinical pathway integration.