['The immune system has been shown to play an important role in gastrointestinal stromal tumor (GIST). The neutrophil-to-lymphocyte ratio (NLR) in blood is an easily assessable parameter of systemic inflammatory response. The aim of this study was to determine whether the NLR is prognostic in GIST.', 'A total of 339 previously untreated patients with primary, localized GIST operated at our institution between 1995 and 2010 were identified from a prospectively collected sarcoma database. NLR was assessed preoperatively. Patients who received adjuvant imatinib treatment were excluded from the analysis (n = 64). Cox regression models were calculated and correlation analyses were performed.', 'On univariate analysis, NLR was associated with recurrence-free survival (RFS) (P = 0.003, hazard ratio 3.3, 95 % confidence interval 1.5-7.4). Patients with a low NLR had a 1- and 5-year RFS of 98 and 91 %, compared with 89 and 76 % in those with a high NLR. The median RFS was not reached. Positive correlations were found between NLR and mitotic rate (Pearson correlation coefficient [r] = 0.15, P = 0.03), and NLR and tumor size (r = 0.36, P = 0.0001). RFS in patients with a GIST >5 cm with low NLR was significantly longer compared to patients with high NLR (P = 0.002). Flow cytometry analysis of freshly obtained GISTs revealed that neutrophils constituted a minimal percentage of intratumoral immune cells.'] Is blood neutrophil-to-lymphocyte ratio prognostic in gastrointestinal stromal tumor?