Taken together, it is of interest that the robust three-gene CD4+ T cell signature we now validate parallels the STAT3-dependent transcriptional pattern observed in the malignant Sézary cells of individuals with the leukaemic variant of cutaneous T cell lymphoma, in which up-regulated PIM1 and SOCS3 is specifically described [37, 38]. Here, CD4 is linked to primary cutaneous T-cell non-Hodgkin lymphoma.