Exploration of Targeted Anti-tumor Therapy

Table 2. Evidence maturity and clinical readiness of reviewed biomarker applications.

Biomarker domain	More established use	Promising but not yet practice-shaping	Investigational/conceptual use
FES PET/CT	Problem-solving whole-body ER mapping in selected ER-positive disease when receptor status or disease extent is uncertain.	Refining endocrine-treatment selection and biopsy targeting in heterogeneous disease.	Routine response-adaptive escalation/de-escalation based on FES patterns alone.
HER2-targeted PET	No broad routine indication; use remains mainly specialised and problem-solving.	Detection of suspected HER2 conversion/heterogeneity when biopsy is infeasible or inconclusive.	PET-directed anti-HER2 treatment selection without prospective outcome validation.
FDG PET/CT under immunotherapy	Whole-body metabolic assessment when conventional imaging is equivocal or bone-dominant disease limits RECIST.	Immunotherapy-aware interpretation of atypical response patterns in TNBC.	Treatment continuation, discontinuation, or escalation based on a single early PET scan.
FDG PET/CT + ctDNA	ctDNA genotyping in selected metastatic settings; PET for spatial disease assessment.	Combined risk stratification and surveillance concepts in trial settings.	Routine treatment de-escalation or escalation based only on early combined biomarker kinetics.

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ctDNA: circulating tumour DNA; ER: oestrogen receptor; TNBC: triple-negative breast cancer; HER2: human epidermal growth factor receptor 2; PET/CT: positron emission tomography/computed tomography.

Supplementary materials

The supplementary figures for this article are available at: https://www.explorationpub.com/uploads/Article/file/1002398_sup_1.pdf.

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Acknowledgments

During the preparation of this work, the authors used ChatGPT (OpenAI) for language editing and to improve clarity and structure of the manuscript. After utilizing the tool, the authors reviewed and edited the content as necessary and take full responsibility for the final content of the publication.

Author contributions

JZ and JZY: Writing—original draft, Writing—review & editing. Both authors read and approved the submitted version.

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