Below are evidence-grounded limitations reported across the provided research dataset, visualized from the cited numeric summaries where available. (Confidence varies by claim; I only state what the sources support.)
The provided review cites stage-specific sensitivity for CancerSEEK (Stage I ~43%) and reports that another methylation-based MCED approach achieves sensitivity >90% at later stage, illustrating stage dependence and the difficulty of early-stage detection.
The same review reports that even with high specificity, PPV can vary widely across programs and populations, which complicates clinical interpretation of positives in low-prevalence screening contexts.
For EV-based liquid biopsy in oncolytic adenovirus therapy, the provided study reports both promise and explicit limitations: clinical validation is needed, mouse-to-human generalization is limited, dynamics with repeated dosing/combination therapies are unclear, and EV isolation by ultracentrifugation may hinder clinical scalability.
The bar heights are a non-metric visualization of how many distinct translation/scalability limitations were explicitly stated in the provided EV-biomarker source, not experimentally measured values.
A provided HRD-focused review reports assay heterogeneity and notes that non-BRCA HRD concordance across platforms can be ~60β70%, implying that current liquid biopsyβadjacent HRD diagnostics can disagree on who is HRD-positive.
| Limitation theme | What it looks like in practice | Evidence from provided sources |
|---|---|---|
| Early-stage sensitivity | Lower sensitivity at Stage I; performance improves with later stage. | |
| PPV variability | Even with high specificity, PPV can be modest in screening-like contexts. | |
| Standardization & harmonization | Cross-study reproducibility is constrained by workflow and threshold differences. | |
| Clinical validation gap | Many approaches need prospective/clinical validation; translation from models is uncertain. | |
| Platform disagreement | Different assay definitions can classify different patients as biomarker-positive. | |
| Scalability of EV workflows | EV isolation methods used in research may not map cleanly to clinical throughput. |
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