Since miR-21, miR-221 and miR-222 up-regulation has been associated with breast cancer aggressiveness and resistance to antineoplastic therapies [16–19], NCL exerts a critical pro-tumorigenic function by regulating their biogenesis at the post-transcriptional level, thus enhancing their maturation from pri- to pre-miRNAs [11]. The gene discussed is NUCLEOLIN; the disease is breast carcinoma.