Bhateja P, et al. - In this study involving patients with stage III and IV non-small cell lung cancer (NSCLC) who also had linked genomic and clinical data, researchers investigated the frequency and prognostic value of retinoblastoma gene (RB1) mutation. The primary study focus was median overall survival (OS). In 8.2% of NSCLC patients, RB1 mutation was present. For wild-type (wt) RB1 and for mutant RB1, the estimated median OS was 28.3 months and 8.3 months, respectively. Findings revealed a correlation between RB1 mutation and lack of response to immunotherapy. To better facilitate comparisons with SCLC, they assessed RB1 mutation in locally advanced and advanced NSCLC. Overall 75% of patients with SCLC had RB1 mutation and, in these subjects, a significantly shorter OS was reported in relation to wt RB1. Rather than simple regulation of cell cycle or response to chemotherapy, a more complicated mechanism was suggested based on different outcomes of RB1 mutation noted among lung cancer subtypes.