To examine whether miR-339-5p can regulate MDM2 protein levels, human colorectal cancer HCT116 p53+/+, HCT116 p53−/−, RKO p53+/+ and RKO p53−/− cells were transfected with miR-339-5p mimic or scrambled miRNA control (miR-con). This evidence concerns the gene TP53 and colorectal cancer.