Histopathology-based assessment of the tumour microenvironment in gastrointestinal cancers: practical approaches to prognostication and treatment stratification

The tumour microenvironment (TME) is a key factor in carcinogenesis by affecting tumour growth, invasion, metastasis, and drug resistance. Histopathology and immunohistochemistry provide accessible and reproducible methodologies for TME evaluation, with growing evidence supporting their prognostic and predictive significance in gastrointestinal cancers. This commentary examines four papers published in the Journal of Pathology: Clinical Research that illustrate this methodology across various gastrointestinal cancers. The Tumour Microenvironment Score, Combined Immune Checkpoint Stromal Score, Immune Score for Gastric Cancer, and the multicomponent microenvironment and tumour inflammatory features panel have been developed to assess TME characteristics in colorectal cancer, gastric cancer, and gastroenteropancreatic neuroendocrine neoplasm. The reviewed studies demonstrate that basic morphological characteristics together with the expression of immune checkpoint markers and immune cell markers enable the development of effective clinical tools to enhance risk assessment and treatment planning. These practical, cost-effective, and promising methods need to undergo extensive multicentre testing with established protocols, digital pathology, and molecular information integration.