FGFR1 and laryngotracheoesophageal cleft: Recently, BGJ398-insensitive cells (NCI-H1703, HCC95 and Calu-3) were shown to express low mRNA and protein level of FGFR1 even in the presence of FGFR1 amplification, indicting that both FGFR1 amplification and protein overexpression are required for the efficacy of FGFR-TKI in LC.24 Moreover, FGFR1 mRNA and protein expression, rather than FGFR1 amplification, was also reported to predict sensitivity to FGFR-TKIs in LC and head and neck squamous cell carcinoma.25, 26