Stimulation with fibroblast growth factor 2 (FGF2) further induced invasive sprouting, while blocking the FGF/R axis resulted in a significant reduction of sprouting in vitro and in vivo.<h4>Conclusion</h4>The FGF/R axis is a key driver of SCLC metastatic spread in the YAP1-dominant subtype. Here, YAP1 is linked to small cell lung carcinoma.