Pathological assessment of tertiary lymphoid structures in pancreatic cancer: development and validation of a novel hematoxylin-eosin based classification

Introduction Although TNM staging is a well-established system, improvements to guide individualized patient care, especially in regards to immunotherapy, are sought. Recent studies pointed out tertiary lymphoid structures (TLS) to be a predictive biomarker for immunotherapy efficacy in many solid tumors; however, its role in pancreatic cancer (PCa) is still unknown. Our aim was to develop and validate a standardized scoring system for the quantification of TLS in PCa.