MiR-34a is considered to act as a tumor suppressor miRNA, since of the 700 to date experimentally validated miR-34a targets,27 many genes are implicated in the control of cellular proliferation (that is, cyclins, cyclin-dependent kinases, MYCN, NOTCH1, MDMX), apoptosis (BCL2, SIRT1 and BIRC5), senescence (E2F3), cancer stem-like cell phenotype (CD44, NANOG and SOX2), motility (SNAI1, MET and AXIN2) or immune evasion (PD-L1, DGKζ). This evidence concerns the gene CD44 and cancer.