The miR-221-222 cluster promotes tumorigenesis by downregulating tumor suppressors such as the pro-apoptotic p53-upregulated apoptosis regulator.[49] Emerging evidence implicates this miRNA family in dexamethasone resistance mechanisms.[50] Specifically, miR-221-222 overexpression confers dexamethasone resistance in MM.1S cells, while anti-miR-221-222 oligonucleotides partially restore dexamethasone sensitivity in resistant MM.1R cells. This evidence concerns the gene TP53 and neoplasm.