Cancer of Unknown Primary Most Suggestive of Colorectal Origin With Microsatellite Instability-high Status and High Tumor Mutation Burden Including NTRK Fusion.

Background/Aim: Cancer of unknown primary (CUP) is associated with a poor prognosis. Recent advances in comprehensive genomic profiling (CGP) have made it possible to detect actionable mutations in CUP cases, which allows the inference of the primary tumor site. This report demonstrates CUP most suggestive of colorectal origin and highlights how CGP can significantly impact treatment decisions and outcomes. Case Report: fusion in addition to radiological examinations, colorectal cancer was the most suspected diagnosis. Conclusion: CUP is generally associated with poor prognosis. Comprehensive genomic profiling (CGP) offers a promising avenue for discovering personalized and potentially effective therapeutic strategies.