TP53 and B-cell chronic lymphocytic leukemia: Furthermore, low miR-15a-5p and miR-16-5p levels induce the upregulation of another target, TP53, that activates the expression of miR-34b-3p and miR-34c-5p and causes the reduction of ZAP-70 levels, leading to an indolent B-CLL phenotype [160].