For example, a therapy with the vector-encoded pair miR-15a and miR-16-1 has been proposed for the treatment of chronic lymphocytic leukaemia (CLL) [13]; The microRNA cluster miR-216a/217 was reported to target genes PTEN and SMAD7 to induce the epithelial-mesenchymal transition, which can promote the drug resistance and recurrence of liver cancer [14]. The gene discussed is PTEN; the disease is B-cell chronic lymphocytic leukemia.