Through in vitro functional study, Noh et al. demonstrated that less efficient miRNA processing caused by knockdown of DROSHADICER and DGCR8 is responsible for reduced levels of mature forms of tumor-suppressive miRNAs, and finally facilitates breast cancer cell invasion by upregulating the expression of urokinase-type plasminogen activator (uPA) [39]. The gene discussed is PLAU; the disease is breast carcinoma.