Guiding Large Language Models for Biomedical Entity Linking via Restrictive and Contrastive Decoding

Zhenxi Lin, Ziheng Zhang, Jian Wu, Yefeng Zheng, Xian Wu


Abstract
Biomedical entity linking (BioEL) aims at mapping biomedical mentions to pre-defined entities. While extensive research efforts have been devoted to BioEL, applying large language models (LLMs) for BioEL has not been fully explored. Previous attempts have revealed difficulties when directly applying LLMs to the task of BioEL. Possible errors include generating non-entity sentences, invalid entities, or incorrect answers. To this end, we introduce LLM4BioEL, a concise yet effective framework that enables LLMs to adapt well to the BioEL task. LLM4BioEL employs restrictive decoding to ensure the generation of valid entities and utilizes entropy-based contrastive decoding to incorporate additional biomedical knowledge without requiring further tuning. Besides, we implement few-shot prompting to maximize the in-context learning capabilities of LLM. Extensive experiments demonstrate the effectiveness and applicability of LLM4BioEL across different BioEL tasks and with different LLM backbones, and the best-performing LLM4BioEL variant outperforms the traditional and LLM-based BioEL baselines.
Anthology ID:
2025.findings-emnlp.1292
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2025
Month:
November
Year:
2025
Address:
Suzhou, China
Editors:
Christos Christodoulopoulos, Tanmoy Chakraborty, Carolyn Rose, Violet Peng
Venue:
Findings
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
23745–23759
Language:
URL:
https://preview.aclanthology.org/author-page-yu-wang-polytechnic/2025.findings-emnlp.1292/
DOI:
10.18653/v1/2025.findings-emnlp.1292
Bibkey:
Cite (ACL):
Zhenxi Lin, Ziheng Zhang, Jian Wu, Yefeng Zheng, and Xian Wu. 2025. Guiding Large Language Models for Biomedical Entity Linking via Restrictive and Contrastive Decoding. In Findings of the Association for Computational Linguistics: EMNLP 2025, pages 23745–23759, Suzhou, China. Association for Computational Linguistics.
Cite (Informal):
Guiding Large Language Models for Biomedical Entity Linking via Restrictive and Contrastive Decoding (Lin et al., Findings 2025)
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PDF:
https://preview.aclanthology.org/author-page-yu-wang-polytechnic/2025.findings-emnlp.1292.pdf
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