TTF-1 expression (OR=0.665, 95%CI: 0.472-0.937), smoking index ≤400 (OR=1.72, 95%CI: 1.061-2.789) and ECOG=2 (OR=3.551, 95%CI: 2.133-5.914), extensive-stage (OR=2.487, 95%CI: 1.793-3.451) and SVCS due to lung cancer (OR=2.394, 95%CI: 1.49-3.846) were independent prognostic factors for SCLC patients. This evidence concerns the gene TTF1 and lung cancer.