Like Peter Pan, some cells never grow up. In cancer, undifferentiated stem cells may help tumors such as glioblastoma become more aggressive than other forms of the disease. Certain groups of genes are supposed to help cells along the path to maturity, leaving their youthful “stemness” behind. This requires sweeping changes in the microRNAome—the world of small non-coding material, known as microRNAs, that control where and when genes are turned on and off. Many microRNAs are tumor-suppressive; in cancer, the microRNAome is distorted and disrupted. Recent work by researchers at Brigham and Women’s Hospital pinpoints critical changes in an enzyme known as DICER, which create a cascade of effects on this microRNAome. The team identified primary actors circ2082, a circular RNA, and RBM3, an RNA-binding protein, which form a complex with DICER to trap it in the nucleus of glioblastoma cells, therefore disrupting the cytoplasmic microRNAome. Findings are published in Science Advances.