ALK and mature T-cell and NK-cell non-Hodgkin lymphoma: The correlation between serum cytokines and the prognosis of PTCL subtypes was explored by a study, which measured 34 cytokines in serum samples from 121 PTCL patients (PTCL-NOS, n = 55; AITL, n = 44; ALK− ALCL, n = 22) [48].