DISSECTING THE HETEROGENEITY OF GASTRIC CANCER AT THE SINGLE CELL LEVEL

Abstract

Heterogeneity between and within gastric cancers (GCs) represents a significant impediment in disease management, underpinned by a poor understanding of lineage-states resident across distinct GC subtypes. We generated a large single-cell atlas of GC (>200,000 cells) from primary gastric tumor samples representing clinical stages and Lauren's histological subtypes. We identified 34 distinct cell-lineage states, connected via developmental trajectories and previously unreported rare cell populations. We observed increased plasma cell proportions as a feature of diffuse-type tumors associated with epithelial KLF2, and a stage-wise accrual of novel cancer-associated fibroblast sub-populations marked concurrently by high FAP and INHBA co-expression. Single-cell comparisons between patient-derived organoids (PDO) and primary tumors highlighted inter- and intralineage similarities and differences. We complement these findings using spatial transcriptomics, orthogonal validation in independent bulk RNA-seq cohorts, and functional demonstration in in vitro and in vivo models. Our results identify unique cancer-lineage programs delineating both intra- and inter-patient differences in the tumor milieu, providing a high-resolution molecular resource for GC translational studies.