This is often associated with downregulation of miR-34a expression in both hematologic and solid malignancies.18, 20, 21, 22, 23, 24 Due to the implication of miR-34a in multiple feedback loops, which can be strongly affected by the therapeutic dose of miR-34a mimic, it is important to consider potential effects of miRNA-based anti-cancer therapy in the context of disrupted or insufficient p53 function. This evidence concerns the gene TP53 and cancer.