Ishteiwy et al. reported that miR-27b was reduced in prostate cancer and that introduction of miR-23b/-27b in the lines of the cells of prostate cancer, which are metastatic and castration-resistant, was responsible for a sharp drop in the activity of Rac1 with unchanged levels, but that resulted in increased levels of the inhibitor of tumour, E-cadherin [13]. The gene discussed is RAC1; the disease is neoplasm.