Reframing early gastric carcinogenesis through lineage, niche, and evolution.

Early gastric cancer is still commonly conceptualized as the endpoint of a linear sequence from chronic gastritis to intestinal metaplasia, dysplasia, and invasion. Yet recent single-cell, spatial, genomic, and functional studies indicate that this model incompletely captures the biology of early gastric carcinogenesis. Malignant potential is established progressively within a precancerous gastric field already shaped by somatic evolution, chronic inflammatory injury, and epithelial lineage distortion. Within this field, progression is concentrated in a restricted set of precursor states, particularly incomplete, hybrid, and stem-like metaplastic populations that display plasticity, persistence, and increasing compatibility with a supportive microenvironment. Fibroblast niche remodeling, immune protection loss, endothelial rewiring, genomic instability, epigenetic drift, and selective retention of advantageous molecular alterations further promote malignant commitment. In parallel, diffuse gastric cancer appears to follow a distinct route that may arise independently of conventional intestinal metaplasia through E-cadherin-deficient epithelial transformation and downstream chromatin reprogramming. Here, we synthesize recent evidence to propose an updated framework for early gastric carcinogenesis based on field evolution, lineage instability, ecosystem support, and pathway divergence. Rather than replacing the classical Correa cascade, this framework seeks to refine it by shifting the unit of risk assessment from histologic stage alone to biologically defined precursor states shaped by lineage instability, clonal persistence, niche permissiveness, and pathway-specific molecular constraints. This perspective shifts the emphasis of prevention from detecting smaller cancers to identifying and intercepting biologically committed precursor states before invasion occurs.