LAUSR

The macrophage inflammatory protein 1α (MIP‐1α) is anticipated to have a role in extranodal natural killer (NK)/T‐cell lymphoma (ENKTL) because the expression of MIP‐1α is related to Epstein–Barr virus (EBV) latency in EBV‐related non‐Hodgkin lymphoma cells. Thus, we measured the serum level of MIP‐1α in 69 patients with ENKTL using frozen serum samples that were archived at diagnosis. As serum level of MIP‐1α was not detectable in 19 patients (range: 0–24.37 pg/mL), patients were dichotomized into positive (n = 50) and negative (n = 19) MIP‐1α groups according to the presence of detectable level of MIP‐1α in serum. MIP‐1α‐positive group showed a significantly poor overall survival (OS) in comparison with the MIP‐1α‐negative group (p = 0.004). In the subgroup analysis, the positivity of MIP‐1α was significantly associated with OS in patients with stage IIIE/IV and a detectable level of EBV DNA (p = 0.002 and 0.032, respectively). Multivariate analysis also showed that the positivity of MIP‐1α was independently associated with worse OS together with bone marrow involvement (p = 0.002). An in vitro study with patient‐derived ENKTL tumour cells showed the expression of CCR1 and CCR5 on the surface of tumour cells (28% and 14%, respectively) , and the addition of MIP‐1α to the culture media of tumour cells increased cell growth supporting the negative impact of MIP‐1α on the prognosis of ENKTL patients. In conclusion, serum levels of MIP‐1α could predict survival outcomes in patients with ENKTL. Therefore, MIP‐1α should be considered for prognostication and a potential therapeutic target. Copyright © 2016 John Wiley & Sons, Ltd.