PIWIL3 belongs to the PIWI argonaute proteins involved inthe maturation of the Piwi-interacting RNAs (piRNAs), small noncodingRNAs that differ from miRNAs.20 Althoughmostly present in normal testis tissue, PIWIL3 has been reported tobe aberrantly expressed in a variety of cancers, playing importantroles in tumorigenesis.21,22 When the authors depletedPIWIL3 in MCF7 cells, increased miRNA levels and growth defects weredetected, similar to the behavior observed for MCF7 cells treatedwith enoxacin. Here, PIWIL3 is linked to cancer.