RB1 and small cell lung carcinoma: Extensive-stage SCLC (ES-SCLC) approximately composes 2/3 of all diagnosed cases of SCLC [3], Although the majority of ES-SCLC occurs mutation of tumor protein p53 (TP53) (90%) and retinoblastoma1(RB1) (65%), the target driven gene is not clear, which leads to limited progression in the treatment of ES-SCLC [4].