miR-34a-5p is overexpressed in HTLV-1-transformed cell lines and ATLL samples (19, 21); its targets identified in HTLV-1-transformed cell lines include the protein deacetylase SIRT1, the pro-apoptotic protein BAX, and the anti-apoptotic protein BIRC5 (Survivin) (21). Here, BIRC5 is linked to adult T-cell leukemia/lymphoma.