Mechanistic studies revealed that NSE might downregulate the expression of neuroblastoma suppressor of tumorigenicity 1 (NBL1) by interacting with NBL1, thereby attenuating the competitive inhibitory effect of NBL1 on BMP2 and enhancing the interaction between BMP2 and BMPR1A; this, in turn, may activate the BMP2/Smad/ID1 pathway and promote SCLC stem cell-like characteristics. This evidence concerns the gene ID1 and small cell lung carcinoma.