High IL-6 expression in the tumor microenvironment is associated with poor prognosis of patients with extranodal natural / killer T-cell lymphoma (ENKTL).

Objectives: Extranodal natural/killer T-cell lymphoma (ENKTL) is a rare subtype of T cell non-Hodgkin's lymphoma. Current clinical prognostic models for ENKTL still have their limitations. Validated prognostic models for ENKTL have not yet been established. Methods: Tumor microenvironment IL-6 was measured by immunohistochemistry in 78 ENKTL patients. Results: Patients with negative IL-6 expression in the tumor microenvironment have a longer PFS (56.0 months vs. 25.6 months, p < 0.001) and OS (96.0 months vs. 43.3 months, p < 0.001). In the multivariate analysis, tumor microenvironment IL-6 [p = 0.048, HR = 1.76(1.00-3.08)] and extranodal involvement [p = 0.001, HR = 2.69(1.50-4.82)] were independent prognostic factors for PFS. Tumor microenvironment IL-6 [p = 0.033, HR = 2.69 (1.08-6.67)], Ann Arbor stage [p = 0.002, HR = 2.77 (1.47-5.23)] and B symptom [p = 0.027, HR = 2.02 (1.08-3.78)] were independent prognostic factors for OS. Expert opinion: A high IL-6 expression was related to poor survival, which may be a valuable biomarker for prognostic evaluation at baseline in ENKTL. These results showed that anti-IL-6R may be a potential targeted therapy for the treatment of advanced or relapsed ENKTL.