RUNX1 and cancer: 19 showed that miR‐378‐mediated suppression of Runx1 alleviated the aggressive phenotype of triple‐negative MDA‐MB‐231 human breast cancer cells. Playing the role of cancer inhibitor, miR‐20a‐5p has been found to be downregulated in the majority of cancer cells. For example, miR‐20a‐5p was confirmed to repress MICA and MICB expression by binding to the mRNA 3′‐UTRs in human cancer cells (mainly HeLa, 293T, DU145 cells) 20. Meanwhile, miR‐20a‐5p was also experimentally verified as new pharmacogenomic biomarkers for metformin in MCF‐7 or MDA‐MB‐231 cell lines 21.