Aberrant FGF19 Expression Is Associated with Prognosis and Radiosensitivity in Gastric Cancer

Objective. To evaluate fibroblast growth factor 19 (FGF19) expression in gastric cancer and its association with clinicopathological features, prognosis, and radiosensitivity. Methods. FGF19 expression patterns and prognostic significance were analyzed using the TCGA-STAD dataset. Immunohistochemistry was performed on tumor tissues and matched adjacent tissues obtained from 115 surgical patients and 48 patients undergoing radiotherapy at the Second Affiliated Hospital of Anhui Medical University between 2021 and 2025. Paired chi-square tests, regression analyses, Kaplan–Meier survival estimates, and logistic regression models were used to assess clinical correlations and radiosensitivity. Results. FGF19 expression was significantly higher in gastric cancer tissues than in adjacent tissues in both the TCGA cohort and the clinical cohort (p < 0.001). High FGF19 expression was associated with shorter recurrence-free survival but not overall survival. Subgroup analyses revealed poorer recurrence-free survival among female and Caucasian patients with high FGF19 levels. Immunohistochemical staining confirmed marked overexpression in tumor tissues (p < 0.001). Elevated FGF19 expression was also associated with reduced radiosensitivity (p = 0.013; OR = 7.014). Conclusion. FGF19 is upregulated in gastric cancer and is associated with increased recurrence risk and diminished radiosensitivity. These findings suggest that FGF19 may serve as a useful biomarker for predicting recurrence and radiotherapy response.