TP53 and neoplasm: By using in vitro tumor cell lines they firstly confirmed the association between miR-155 expression and the resistance to chemotherapeutic agents commonly used to treat patients and then they identified a miR-155/p53-negative feedback loop, involved in chemo-resistance, by which p53 inhibits the expression of miR-155 through the direct binding in the downstream region of miR-155 that, in turn, binds to the 3′untranslated regions (UTR) of TP53 gene.