RRM2 and triple-negative breast carcinoma: Additionally, miR-20-5p could target ribonucleotide reductase subunit M2 (RRM2) to regulate the gemcitabine chemosensitivity in pancreatic cancer cells and enhance the growth of triple-negative breast cancer (TNBC) cells by targeting Runx3, Bim, and p21 [20, 22].