EAAI Journal 2026 Journal Article
Cross-stain knowledge distillation for low-cost lung cancer programmed death ligand-1 assessment with multi-granularity multiple instance learning
- Yi Shi
- Chong Ge
- Fang Zhao
- Anli Zhang
- Ao Li
- Haibo Wu
- Minghui Wang
Accurately assessing programmed death ligand-1 (PD-L1) status, recognizing patients potentially responsive to immunotherapies. Since immunohistochemistry (IHC) staining is gold standard in identifying molecular biomarker but often expensive and unattainable, routine hematoxylin and eosin (H&E) staining offers a low-cost alternative. However, H&E images primarily reveal morphological knowledge and inherently lack PD-L1-related molecular information, resulting in a severe mono-stain knowledge limitation. Additionally, most existing approaches analyze gigapixel whole-slide images at only a single magnification, which fails to unravel complex pathological information across granularities, leading to a significant uni-granularity information limitation. Therefore, we propose an innovative cross-stain knowledge distillation with multi-granularity framework, namely CroSMuG. First, to alleviate uni-granularity information limitation, a new multi-granularity multiple instance learning framework is introduced. This is based on macro-micro dual branches, which comprises a macro-branch and a micro-branch to extract global and local pathological information. Furthermore, we develop a novel cross-stain knowledge distillation strategy featuring triple-united distillation loss. Specifically, this approach introduces globality-, locality- and task-aware knowledge distillation, enabling the H&E-based predictive network as a student to learn crucial molecular knowledge from an IHC teacher network. Extensive experiments are conducted on diverse real-world datasets from multiple medical centers, and CroSMuG achieves the superior performance with area under the curve (AUC) of 83. 6 % on internal dataset and 81. 2 % on external dataset. These results highlight the generalizability of CroSMuG for accurate H&E-based PD-L1 assessment, offering the potential for practical applications in lung cancer immunotherapy decision-making in clinical practices.