Fgfr2-Tsc22d1, A Novel Fgfr2 Fusion Gene Identified In A Patient With Colorectal Cancer: A Case Report

BACKGROUND The FGFR signaling pathway is activated in multiple tumor types through gene amplifications, single base substitutions, or gene fusions. Novel FGFR gene fusions may represent candidate targets for the development of tyrosine kinase inhibitors. CASE SUMMARY Herein, we report a patient with colorectal cancer (CRC) harboring a novel FGFR2 fusion gene. A 59-year-old man felt discomfort in his right upper abdomen with loss of appetite for 6 mo. An abdominal computed tomography scan revealed the existence of a space-occupying lesion in the ascending colon. The pathological diagnosis was a poorly differentiated adenocarcinoma. Subsequent biopsy specimen was subjected to next-generation sequencing analysis, and a novel FGFR2-TSC22D1 fusion with complete kinase structure of FGFR2 protein was identified. CONCLUSION We report the first case of CRC harboring FGFR2-TSC22D1, which enriches the FGFR2 fusion spectrum. FGFR2 inhibitors might be effective in the later treatment for this patient.