In the meantime, it would also be interesting to prospectively correlate FAK expression and activity in formalin-fixed paraffin-embedded (FPPE) human lung cancer tissues with response rates to FAK TKI of corresponding patient-derived xenograft models (immediate transfer of human cancer cells from NSCLC or SCLC patients to recipient immunodeficient mice). This evidence concerns the gene PTK2 and small cell lung carcinoma.