[NGS (Next-Generation Sequencing) in Tumor Pathology: Principles, Strategies and Practical Limitations]

Next-generation sequencing (NGS) has become a cornerstone of tumor pathology, enabling the simultaneous characterization of multiple somatic alterations for diagnostic, prognostic, and theragnostic purposes. The available strategies (from targeted gene panels to comprehensive approaches such as whole exome or whole genome sequencing) as well as enrichment methods and sequencing platforms, must be selected according to the clinical question, the expected alterations, and the analytical constraints. The reliability of results depends on mastering the entire analytical workflow, from library preparation to bioinformatic processing and variant interpretation. This article describes the key steps of the NGS workflow, the parameters governing analytical performance (sequencing depth, coverage, and variant allele frequency) as well as the limitations inherent to each strategy and the interpretative pitfalls associated with tumor material quality. It emphasizes that integrating NGS results within the morphological and clinical context remains essential, and that variant interpretation constitutes a full medical act in its own right.