In breast cancer, PIWIL1 combines with piR-36712 to form RISC, which is targeted to degrade SEPW1P, a retroprocessed pseudogene of SEPW1, and subsequently reduces SEPW1 expression through competition of SEPW1 mRNA with SEPW1P RNA for microRNA-7 and microRNA-324 and inhibits proliferation, migration and invasion [129]. Here, PIWIL1 is linked to breast cancer.