In our panel of hematopoietic neoplasias, MAC-1/2A/2B were conspicuously sensitive to a selective JAK2 inhibitor TG101348, surpassing even JAK2V617F mutation cells, while responding unremarkably to methotrexate or SAHA used clinically in treating CTCL. Here, JAK2 is linked to primary cutaneous T-cell non-Hodgkin lymphoma.