MiRNAs exert their function through base-paring to the 3′ UTR of their target gene with imperfect complementarity.7 MiR-101 has many validated oncogenic targets, including FOS, EZH2, MCL-1 and ROCK2.23, 24, 25, 26 It has been reported that miR-101 could inhibit migration and invasion by targeting AP-1 pathway in hepatoma cells,27 and a more recent study shows that loss of miR-101 positively correlates with the upregulation of COUP-TFII activity, which contributes to prostate cancer metastasis.28 These data suggest a powerful tumour suppressive activity of miR-101 in human cancers. The gene discussed is FOS; the disease is prostate carcinoma.