Bridging the Modality Bottleneck in Pathology MIL through Molecularly Guided Feature Adaptation
Abstract
Multiple instance learning (MIL) is the dominant framework for whole-slide image analysis in computational pathology, typically combining a frozen patch encoder, a projection layer, and a slide-level aggregator. While encoders and aggregators have been extensively studied, the projection layer remains a largely morphology-only bottleneck. This limits endpoints such as biomarker status and survival, which are governed by a molecular state that is not fully captured by H&E morphology. We introduce Molecularly Informed Staining Transform (MIST), a plug-in replacement for the MIL projection layer that uses paired spatial transcriptomics only during training to construct virtual molecular stains. MIST clusters gene expression profiles into cross-modal prototypes, anchors them in the frozen foundation model feature space, and uses them to reorganize H&E patch features along molecularly guided axes. It requires no transcriptomics at inference and can be inserted before standard MIL aggregators. We evaluate MIST across 23 downstream tasks and 8 MIL aggregators. MIST improves 240 of 256 configurations over the standard projection layer, with an average gain of +3.5%, observed consistently across endpoint types: +5.2% on survival prediction, +3.3% on tissue subtyping, and +2.6% on biomarker prediction. Ablations confirm that gene-derived prototypes are the primary source of the gains, while spatial, biological, and pathological analyses show that cross-modal prototype affinities capture spatially coherent molecular programs from H&E alone.
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BibTeX
@misc{xing2026bridging,
title = {{Bridging the Modality Bottleneck in Pathology MIL through Molecularly Guided Feature Adaptation}},
author = {Yucheng Xing and Pei Liu and Jingying Ma and Ruping Hong and Jiangdong Qiu and Tianyu Liu and Kai He and Ling Huang and Mengling Feng},
howpublished = {arXiv},
year = {2026},
month = nov,
doi = {10.48550/arxiv.2605.16392},
eprint = {2605.16392},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2605.16392},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Bridging the Modality Bottleneck in Pathology MIL through Molecularly Guided Feature Adaptation
AU - Yucheng Xing
AU - Pei Liu
AU - Jingying Ma
AU - Ruping Hong
AU - Jiangdong Qiu
AU - Tianyu Liu
AU - Kai He
AU - Ling Huang
AU - Mengling Feng
PY - 2026
DA - 2026/11/04
PB - arXiv
DO - 10.48550/arxiv.2605.16392
UR - https://arxiv.org/abs/2605.16392
AB - Multiple instance learning (MIL) is the dominant framework for whole-slide image analysis in computational pathology, typically combining a frozen patch encoder, a projection layer, and a slide-level aggregator. While encoders and aggregators have been extensively studied, the projection layer remains a largely morphology-only bottleneck. This limits endpoints such as biomarker status and survival, which are governed by a molecular state that is not fully captured by H&E morphology. We introduce Molecularly Informed Staining Transform (MIST), a plug-in replacement for the MIL projection layer that uses paired spatial transcriptomics only during training to construct virtual molecular stains. MIST clusters gene expression profiles into cross-modal prototypes, anchors them in the frozen foundation model feature space, and uses them to reorganize H&E patch features along molecularly guided axes. It requires no transcriptomics at inference and can be inserted before standard MIL aggregators. We evaluate MIST across 23 downstream tasks and 8 MIL aggregators. MIST improves 240 of 256 configurations over the standard projection layer, with an average gain of +3.5%, observed consistently across endpoint types: +5.2% on survival prediction, +3.3% on tissue subtyping, and +2.6% on biomarker prediction. Ablations confirm that gene-derived prototypes are the primary source of the gains, while spatial, biological, and pathological analyses show that cross-modal prototype affinities capture spatially coherent molecular programs from H&E alone.
ER -