FGFR-IN-25 (Compound 19E) is an FGFR inhibitor with IC50 values of 1.30 nM for FGFR1 and 0.85 nM for FGFR2, and also acts as a radiosensitizer. It effectively reduces the phosphorylation levels of FGFR1 and its downstream effectors, pAKT and pERK. FGFR-IN-25 exhibits broad-spectrum antitumor activity against gastric, colorectal, liver, breast, triple-negative breast cancers, and glioblastoma. When combined with radiation therapy, FGFR-IN-25 synergistically activates the ROS-Caspase-3-GSDME pathway, downregulates PD-L1 expression, and induces immunogenic cell death, thereby enhancing the antitumor effects.