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Over the last two decades there has been a broad paradigm shift in our understanding of gastric cancer (GC) and its premalignant states from gross histological models to increasingly precise molecular descriptions. In this review we reflect upon the historic approaches to describing premalignant lesions and GC, highlight the current molecular landscape and how this could inform future risk assessment prevention strategies.

BackgroundIntestinal metaplasia (IM) is considered a key pivot point in the Correa model of gastric cancer (GC). It is histologically subtyped into the complete and incomplete subtypes, the latter being associated with a greater risk of progression. However, the clinical utility of IM subtyping remains unclear, partially due to the absence of reliable defining biomarkers.MethodsBased on gene expression data and existing literature, we selected CD10 and Das1 as candidate biomarkers to distinguish complete and incomplete IM glands in tissues from patients without GC (IM-GC) and patients with GC (IM + GC). Immunohistochemical staining of individually subtyped IM glands was scored after blinding by two researchers using tissue belonging to both IM-GC and IM + GC patients. Whole tissue Das1 staining was further assessed using digital image quantification (cellSens Dimension, Olympus).ResultsAcross both cohorts CD10 stained the IM brush border and was shown to have a high sensitivity (87.5% and 94.9% in IM-GC and IM + GC patients respectively) and specificity (100.0% and 96.7% respectively) with an overall AUROC of 0.944 for complete IM glands. By contrast Das1 stained mainly goblet cells and the apical membrane of epithelial cells, mostly of incomplete IM glands with a low sensitivity (28.6% and 29.3% in IM-GC and IM + GC patients respectively) but high specificity (98.3% and 85.1% respectively) and an overall AUROC of 0.603 for incomplete IM glands. A combined logistic regression model showed a significant increase in AUROC for detecting complete IM glands (0.955 vs 0.970). Whole tissue digital quantification of Das1 staining showed a significant association with incomplete IM compared to complete IM, both in IM-GC and in IM + GC patients (p = 0.016 andp = 0.009 respectively, Mann–Whitney test and unpaired t test used). Additionally, complete IM in IM + GC patients exhibited significantly more Das1 staining than in IM-GC patients (p = 0.019, Mann–Whitney test).ConclusionsThese findings suggest that CD10 is an outstanding biomarker for complete IM and Das1 may be useful as a secondary biomarker for IM glands at greater risk of progression irrespective of IM subtype. Overall, the clinical use of these biomarkers could lead to improved patient stratification and targeted surveillance.

Although the incidence of gastric cancer (GC) is declining, it remains a significant global problem. GC is thought to arise via a series of histologically distinct premalignant stages and triggered by chronic Helicobacter pylori infection. Key to this pathway is intestinal metaplasia (IM), an intermediate stage immediately preceding dysplasia and a known risk factor in the progression to GC. This chapter focuses primarily on IM, its histological subtypes, clinical implications, and role in GC progression, and discusses the global surveillance and management guidelines for individuals with IM. The latter part of the chapter addresses the diagnosis and treatment of early GC which is a developing field in Western countries where GC is often diagnosed at an advanced stage.