Tumor suppressor genes TP53 and RB1 were universally inactivated in SCLC, which was once considered a molecularly homogeneous tumor [7], In recent years, the importance of MYC family, KMT2D, PIK3CA, and other gene mutations has been confirmed in patients, xenograft tumor models, mice, and cell levels. Here, RB1 is linked to small cell lung carcinoma.