CDK4 and T-cell acute lymphoblastic leukemia: Conversely, six microRNAs (miR-193b, miR-432-5p, miR-200a, miR-223, Let-7a and miR-21) conferred resistance to treatment with CDK4/6 inhibitors according to studies performed mainly on cell lines deriving from solid tumors (breast, prostate and metastatic melanoma), with the exception of Let-7a and miR-21, which were upregulated in T-cell acute lymphoblastic leukemia/lymphoma cells (Table 2).