Second-line afatinib vs erlotinib for patients with squamous cell carcinoma (SCC) of the lung (LUX-Lung 8 [LL8]): analysis of tumour and serum biomarkers and long-term responders. (February 2017) - Gadgeel, S.M.; Soria, J.C.; Felip, E.; Cobo, M.; Lu, S.; Syrigos, K.; Lee, K.H.; Göker, E.; Georgoulias, V.; Li, W.; Guclu, S.; Isla, D.; et al.