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A pathway-dependency framework for acquired resistance to targeted therapy in EGFR-mutant, KRAS G12C-mutant, and BRAF
Xiaoxiao Li1, Yadong Guo2, Shize Yang1
1Department of Thoracic Surgery, The First Hospital of China Medical University, China Medical University, Shenyang 110000, China.
Abstract:
Targeted therapies have improved outcomes in EGFR-, KRAS G12C-, and BRAF V600E-driven non-small cell lung cancer (NSCLC), but acquired resistance is molecularly and spatially heterogeneous. Driver-specific algorithms and validated biomarkers underpin post-progression care. Determining pathway activity, causal dependency, and a tractable therapeutic vulnerability requires evidence beyond detecting an acquired alteration. We propose a lesion- and time-specific pathway-dependency framework centered on the RAS-RAF-MEK-ERK mitogen-activated protein kinase (MAPK) pathway and the PI3K-AKT-mTOR pathway. It distinguishes three provisional biological states: MAPK-dominant resistance, shared-input MAPK-PI3K reactivation, and a candidate PI3K-enriched/MAPK-low state. A clinical management branch encompasses histologic transformation, central nervous system-limited progression, oligoprogression, and diffuse polyclonal progression and may coexist with a biological assignment. Spatially discordant mechanisms support a mixed assignment, whereas insufficient evidence remains indeterminate. Biological assignment integrates contemporaneous lesion-level findings, clonality, histology, and exploratory pathway readouts; progression pattern guides the clinical branch. The framework complements genotype-based classification and may clarify when better-supported systemic, histology-directed, or local treatment should take precedence. Evidence remains uneven: some driver-specific interventions have established clinical evidence or clinically supported activity, whereas most downstream MAPK strategies and all approaches matched to the candidate PI3K-enriched/MAPK-low state remain investigational. Limited tissue availability, spatial heterogeneity, unstandardized assays, and combination toxicity constrain implementation. Prospective studies should determine whether a locked classifier adds predictive value beyond the initiating driver and acquired genomic alterations. Until prospective validation is available, the framework is best suited to mechanistic interpretation and trial design; routine treatment continues to rely on validated biomarkers and established clinical evidence.
Insights
Acquired resistance in non-small cell lung cancer (NSCLC) is complex. A new framework helps understand pathway activity and guide treatment decisions for better patient outcomes.
Area of Science:
- Oncology
- Molecular Biology
- Genomics
Background:
- Targeted therapies have improved outcomes for specific non-small cell lung cancer (NSCLC) subtypes (EGFR-, KRAS G12C-, BRAF V600E-driven).
- Acquired resistance to these therapies is often molecularly and spatially heterogeneous, complicating post-progression care.
- Current management relies on driver-specific algorithms and biomarkers, but determining causal dependencies and therapeutic vulnerabilities requires deeper insights.
Purpose of the Study:
- To propose a novel framework for understanding and classifying resistance mechanisms in NSCLC.
- To integrate molecular pathway activity (MAPK, PI3K-AKT-mTOR) with clinical progression patterns for improved treatment guidance.
- To differentiate biological states of resistance and inform clinical management strategies.
Main Methods:
- Development of a lesion- and time-specific pathway-dependency framework focusing on MAPK and PI3K-AKT-mTOR pathways.
- Classification of resistance into three provisional biological states: MAPK-dominant, shared-input MAPK-PI3K, and PI3K-enriched/MAPK-low.
- Integration of clinical progression patterns (histologic transformation, CNS-limited, oligoprogression, diffuse polyclonal progression) with biological assignments.
Main Results:
- The framework distinguishes three provisional biological states of resistance.
- It incorporates clinical progression patterns into a management branch, allowing for mixed or indeterminate assignments.
- Biological assignment integrates lesion-level findings, clonality, histology, and pathway readouts, while progression patterns guide the clinical branch.
Conclusions:
- The proposed framework complements genotype-based classification and aids in selecting appropriate treatments (systemic, histology-directed, local).
- While some driver-specific interventions have evidence, many downstream MAPK strategies and PI3K-enriched approaches remain investigational.
- Implementation challenges include limited tissue, heterogeneity, assay standardization, and toxicity; prospective studies are needed for validation, but the framework is valuable for mechanistic interpretation and trial design.
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