PLK1 and neoplasm: miR-34a directly targets the 3’UTRs of numerous oncogenic mRNAs, including ARAF, CD44, CD117, CDK4, c-Met, cyclin D3, cyclin E2, E2F3, Fra-1, Jagged1, MCM2/5, MET, MYCN, Notch1/2, PIK3R2, PLK1, Smad4, SIRT1/6, and VEGFA, which may contribute to its tumor-suppressive role [14, 15, 18, 21, 23, 24, 26–28, 39–41].