miR-34a was selected as a candidate tumor suppressor miRNA based on its frequent deregulation in cancer tissues6, 7, 8 and its ability to regulate the expression of multiple targets implicated in tumorigenesis and cancer progression, such as MYC, MET, CDK4/6, NOTCH1, BCL2, CD44 and many other molecules.9, 10 Broad target specificity of miRNAs, resulting from their short binding motifs in target gene sequences, can be advantageous for simultaneous targeting of multiple tumor-promoting transcripts, but at the same time poses a risk of potential adverse effects. The gene discussed is NOTCH1; the disease is neoplasm.