Personalized signaling pathway analysis of gastrointestinal tumors for patient stratification and drug target evaluation using clinically derived core biopsies.

Aberrant cellular signaling underlies cancer development and progression. Identifying alterations in these pathways yields critical insights for personalized oncology. Clinically, assessing the activation status of signaling proteins complements genetic and histopathological analyses, improving therapeutic evaluation and accuracy. In this study, we employed the high-throughput Western blot system DigiWest for the characterization of gastrointestinal tumors, both retrospectively and in a proof-of-concept direct clinical application. Retrospective analyses of pancreatic and colorectal carcinomas (n = 20) compared with matched normal tissues revealed distinct protein expression and activation patterns differentiating tumor subtypes and defining clinically relevant subgroups. By resolving individualized, treatment-relevant signaling signatures we demonstrate the feasibility of molecular-level personalization in samples with high clinical heterogeneity. In the clinical proof-of-concept, single core needle biopsies from 14 patients with gastrointestinal tumors who underwent Molecular Tumor Board presentation were analyzed. The resulting proteomic profiles uncovered patient-specific, targetable pathway activation patterns and showed concordance with mutational data and therapy recommendations. Collectively, these findings establish DigiWest as a valuable, robust complementary tool to sequencing-based approaches for personalized diagnostics and treatment evaluation in precision oncology.