To determine the role of JAK2/STAT5/PD-L1 pathway in the prognosis of ENKTL patients treated by GM-CSF, we used immunostaining to detect the levels of these three proteins in 21 PTCL patients who received GM-CSF treatment from January 2011 to September 2015, including 14 ENKTL patients, 4 AITL patients and 4 PTCL-NOS patients (Fig. 6A-B). This evidence concerns the gene STAT5A and angioimmunoblastic T-cell lymphoma.