Xie et al. have built up a prognostic 10-gene immune-related signature (ARAF, HDGF, INHBE, LRSAM1, NR1D2, NR3C1, PLXNA1, PML, SP1, and TANK), able to predict SCLC patients' survival; however, this model needs validation as a predictive tool for immunotherapy (51). This evidence concerns the gene HDGF and small cell lung carcinoma.