Consistent with the crucial role of STAT5 signalling in the proliferation of Tcons, CD4+ T cell pSTAT5 MFI was significantly positively correlated with the percentage of Ki-67+ Tcons among CD4+ T cells in peripheral blood from treated patients with CLL (Supplementary Figure S5C). This evidence concerns the gene MKI67 and B-cell chronic lymphocytic leukemia.