FKBP4 and leukemia: Furthermore, overexpression of FKBP51 in human megakaryoblastic leukaemia cells, UT-7/mpl, markedly inhibited calcineurin activity, which was associated with induced resistance to apoptosis mediated by cytokines deprivation, suggesting that FKBP51 could be responsible for megakaryocytes hyperplasia through calcineurin-dependant pathway.