STAT4 and prolymphocytic leukemia: Further studies also need to address (i) additional modes of STAT4 downregulation besides the miR-141/200c upregulation (e.g., epigenetic dysregulation), (ii) the functional impact of further miR-141/200c target genes in the pathogenesis of T-PLL (e.g., downregulation of CADM1, recently shown to be associated with poor prognosis in primary adult T-cell leukemia/lymphoma [34]), and (iii) STAT4 downregulation in other entities of mature T-cell lymphoma.