FGFR1 and osteosarcoma: We applied cells devoid of detectable FGFR1 level: U2OS (osteosarcoma), HCC-15 (lung squamous cell carcinoma) and T47D (invasive ductal carcinoma) as controls, and U2OS-R1 (osteosarcoma cells stably transfected with FGFR1), NCI-H520 (lung squamous cell carcinoma), JIMT-1 (ductal breast carcinoma), COLO-699 (lung adenocarcinoma) and NCI-H1581 (lung large cell carcinoma) cells producing different levels of FGFR1 (Fig. 4a).