Kolkowski et al. reported an increased risk of CTCL in patients treated with ruxolitinib (25), while Mo et al. suggested that upadacitinib might induce CTCL, potentially due to the dysregulation of the JAK3-STAT3 signaling pathway, which is associated with CTCL (22). The gene discussed is STAT3; the disease is primary cutaneous T-cell non-Hodgkin lymphoma.