CellReasoner: a reasoning-enhanced large language model for cell type annotation
1.This paper presents CellReasoner, a lightweight open-source LLM for single-cell type annotation. It achieves expert-level accuracy and interpretability using only 380 chain-of-thought (CoT) exemplars, demonstrating remarkable zero- and few-shot generalization.
2.CellReasoner elevates cell annotation from simple label prediction to a multi-step reasoning task, directly mapping gene expression profiles ("cell sentences") to cell types while outputting interpretable marker-by-marker explanations.
3.The model is trained using a novel three-stage strategy called CRAFT: (1) reasoning scaffold using high-quality CoT samples; (2) knowledge infusion with ~37K Q&A pairs; (3) reasoning mode fusion to restore interpretability and logic after knowledge overload.
4.Despite its compact 7B or 32B scale, CellReasoner matches or outperforms much larger models (e.g., DeepSeek-671B, ChatGPT-4o) in both zero-shot and few-shot annotation across diverse tasks, tissues, and modalities.
5.Unlike cluster-level approaches that propagate errors, CellReasoner works at the single-cell level, enabling local corrections and higher subtype resolution—crucial for complex tissues and immunological profiling.
6.In benchmark tests on PDAC, PBMC3K, and liver datasets, CellReasoner achieves up to 0.97 accuracy in 10-shot settings and adapts across modalities from scRNA-seq to scATAC-seq with minimal retraining.
7.Using a unified "cell sentence" input format derived from top-ranked HVGs, the model standardizes representation across datasets, allowing consistent performance and scalable deployment.
8.The CoT reasoning chains enable the model to mimic expert annotation behavior, e.g., integrating positive/negative marker logic, TCR complex knowledge, and context-aware inference to correctly identify challenging subtypes like CD4 memory T cells.
9.In tests on 181 datasets across 48 cancer types from TISCH2, CellReasoner shows strong generalization but also highlights real-world challenges like inconsistent labeling granularity—emphasizing the need for harmonized cell ontology standards.
10.The model is fully open-source, optimized for consumer GPUs (e.g., RTX 4090), and accessible via HuggingFace. Its efficient LoRA-based fine-tuning and prompt-based design make it highly practical for research labs and clinicians.
11.Compared to traditional reference-based tools like SingleR, CellReasoner eliminates dependency on static atlases and manual marker curation, offering a dynamic, interpretable, and scalable alternative for modern single-cell analysis.
12.This work demonstrates that small, reasoning-activated LLMs can perform complex biological inference with high accuracy, interpretability, and adaptability—paving the way for LLM-based tools across omics, diagnostics, and biomedical discovery.
💻Code:
github.com/compbioNJU/CellRe…
📜Paper:
biorxiv.org/content/10.1101/…
#SingleCell #CellAnnotation #LLM #ExplainableAI #CRAFTtraining #Transcriptomics #scRNAseq #scATACseq #Bioinformatics #CellReasoner