Finally, the E3 ubiquitin ligase HECTH9 (also named HUWEI, ARF-BP1 or MULE) mediates the K63-polyubiquitination of DDX17, which is a cofactor of the Drosha–DGCR8 complex in miRNA biogenesis and a transcriptional co-activator associated with cancer stem-like properties. The gene discussed is DDX17; the disease is cancer.