To determine whether human FGFR1 will be activated in this mouse system we demonstrated, that murine FGFR1 ligands, such as FGF1 and FGF2 can activate human FGFR1 using the human H520 lung cancer cell line that overexpresses FGFR1, (Figure 4C). Here, FGF1 is linked to lung carcinoma.