Cross-Modal Contrastive Learning for the Retrieval of Immunotherapy-Associated Molecular Signatures from Histopathology
Organizations: Signal Theory and Communications Department (TSC) Universitat Politècnica de Catalunya - BarcelonaTech (UPC) · Cancer Biomarkers Research Group (GReBiC) - IRB Lleida
Abstract
Gastric Adenocarcinoma is a leading cause of cancer mortality. Although "Inflamed/Non-Inflamed" subtypes have been proposed to predict immunotherapy response, their identification relies on a costly 10-gene RNA signature. We propose a Cross-modal Contrastive Multiple Instance Learning (CCMIL) framework for cross-modal retrieval, imputing these molecular signatures directly from standard Hematoxylin & Eosin (H&E) slides. By leveraging a supervised contrastive objective, CCMIL aligns visual morphological patterns with molecular phenotypes into a shared latent space. This establishes an interpretable search-by-case retrieval engine, enabling pathologists to query a whole slide image to surface transcriptomically coherent neighbors and approximate RNA signatures without genomic sequencing at inference. Our results demonstrate that this retrieval-first approach captures the continuous phenotypic spectrum of tumor inflammation and yields clinically interpretable attention heatmaps. Furthermore, the learned representation also supports competitive downstream classification, providing a practical molecular pre-screening strategy.
Figures & tables
| Retrieval | ||||||
| Retrieval (Image RNA) | k-NN Classification | |||||
| Model | Q Tgt | R@1 | R@5 | MRR | Acc. | F1 |
| Baseline | Te Tr | – | – | .71 .106 | .57 .129 | .53 .109 |
| Baseline | Te Te | .67 .115 | .89 .086 | .78 .067 | .67 .107 | .65 .074 |
| CCMIL | Te Tr | – | – | .75 0.049 | .68 .080 | .61 .138 |
| CCMIL | Te Te | .72 .085 | .92 .051 | .80 .067 | .71 .155 | .67 .133 |
| Components | Classification | Retrieval | |||||
|---|---|---|---|---|---|---|---|
| THCA | SupConL | ClassL | Acc. | AUC | F1 | R@1 | R@5 |
| ✓ | ✓ | ✗ | .54 .092 | .45 .156 | .66 .069 | .69 .068 | .88 .068 |
| ✓ | ✗ | ✓ | .68 .103 | .68 .073 | .72 .076 | .63 .119 | .84 .068 |
| ✗ | ✓ | ✓ | .72 .106 | .74 .084 | .74 .080 | .60 .069 | .84 .107 |
| ✓ | ✓ | ✓ | .72 .157 | .75 .135 | .76 .112 | .72 .085 | .92 .051 |