Previous studies reported that numerous signalling pathways are associated with the process of EMT in SCLC; these pathways include the Notch,8 Hedgehog9 and focal adhesion kinase (FAK) signalling pathways.10 Among these factors, the highly activated FAK signalling pathway is strongly believed to contribute to triggering EMT in SCLC. The gene discussed is PTK2; the disease is small cell lung carcinoma.