Abstract Background: The Cancer Genome Atlas (TCGA) has defined four molecular subtypes of gastric cancer: Epstein-Barr virus (EBV)- associated, microsatellite instability (MSI)- associated, genomically stable (GS), and chromosomal instability (CIN). These subtypes have distinct clinicopathologic and therapeutic implications. However, the routine determination of these subtypes still relies on multimodal molecular assays that are costly and not universally available. We aimed to develop a weakly supervised deep learning framework that predicts TCGA molecular subtypes directly from hematoxylin and eosin (H accuracy: 0.74 vs. 0.67). The hybrid model also showed improved subtype separability in the UMAP embedding (V-measure 0.74 with TransMIL-MBA vs. 0.65 with ACMIL) and clearer confusion matrices. Conclusions: A weakly supervised multiple instance learning framework combining TransMIL with MBA shows promising performance for predicting TCGA molecular subtypes of gastric cancer directly from H Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 1445.
Jeong et al. (Fri,) studied this question.