Based on this heterogeneity, a TNF family-based prognostic predictive signature was constructed, including TNFRSF25, CD40, TNFRSF10B, TNFSF14, TNFSF13B, TNFRSF1B, TNFRSF21, and RELT, and the signature was shown to possess excellent predictive value for predicting the prognosis of SCLC patients. Here, TNFRSF21 is linked to small cell lung carcinoma.