Oncogenic FGFR3 gene fusions in solid tumors among Chinese cancer patients.

Abstract

e15072 Background: Oncogenic FGFR3 (fibroblast growth factor receptor 3) gene fusions have been identified as driver mutations that lead to the activation of FGFR3 in many solid tumor types and serve as a novel therapeutic target for FGFR inhibitors in clinical development. TACC3 (transforming acid coiled coil 3) is the most common partner of these FGFR3 fusions. Methods: The study enrolled over ten thousand cases of Chinese patients with different types of solid tumors. We performed targeted sequencing assay with our 605 gene panel that covered all the exon and intron regions of the FGFR3 gene, so that we could identify nearly all the FGFR3 translocation events. Results: The prevalence and form of FGFR3 fusions in different tumor types were shown in Table. We identified seven patients harboring FGFR3 fusion events, with six cases of FGFR3-TACC3 and one case of FGFR3-UBE2K. In the seven patients, three of them were also harbored concomitant TP53 gene mutations, and six of them were microsatellite stability (MSS), and one was microsatellite instability-low (MSI-L). Conclusions: FGFR3 gene rearrangements were identified in different solid tumor types in our study, and they were relatively rare compared to other novel mutations. However, clinical testing for the identification of FGFR3 fusions should be prioritized in bladder cancer patients. Consistent with other studies, the most common FGFR3 fusion form was FGFR3-TACC3. Co-occurring genetic alterations in FGFR3 gene fusions cases were also common. From our limited number of cases, most of FGFR3 gene fusions patients were MSS.[Table: see text]