Pre-treatment neutrophil-to-lymphocyte ratio is associated with neutrophil and T-cell infiltration and predicts clinical outcome in patients with glioblastoma

Background: Markers of systemic inflammation are correlated with patient survival in various cancers. The prognostic value of neutrophil-to-lymphocyte ratio (NLR) was compared with that of platelet-to-lymphocyte ratio (PLR) in patients with glioblastoma. The association of NLR with neutrophil and T-cell infiltration was also explored. Methods: A total of 152 patients with glioblastoma were retrospectively analyzed. Clinical information was obtained from electronic medical records. Kaplan-Meier analysis and the Cox proportional hazards models were used to examine the survival function of pre-treatment NLR and PLR in these glioblastoma patients. Neutrophil and CD3(+) T-cell infiltration was assessed by immunohistochemical staining of tissue microarray cores from glioblastomas. Results: Pre-treatment NLR levels were significantly correlated with overall survival (OS) in glioblastoma patients (multivariate hazard ratio = 1.050; 95 % confidence interval, 1.003-1.100; P = 0.037). Despite the correlation between NLR and PLR (R = 0.509, P < 0.001), NLR was superior to PLR as a prognostic factor. High pre-treatment NLR (>= 4 versus < 4) was significantly associated with high neutrophil infiltration and low CD3(+) T-cell infiltration into tumors, and predicted poor OS (mean, 10.6 vs. 17.9 months, P < 0.001). Conclusions: Pre-treatment NLR is of prognostic significance independent of MGMT status and is superior to PLR as a prognostic factor. Our results demonstrate a correlation between elevated peripheral blood NLR levels and increased tumor neutrophil infiltration/ decreased CD3(+) T-cell infiltration.