Fig. 1

ARG1 is expressed in ovarian tumors and its levels correlate with poor prognosis. a, b ARG1 expression in OvCa cell lines and tumor cells obtained from ascites determined by Western blotting and flow cytometry, respectively. The shaded area (in b) represents isotype control staining, whereas the transparent one reflects ARG1 expression. c Representative immunohistochemistry staining of ARG1 in normal ovary (upper left) and ovarian tumor (upper right and lower panels) sections at diagnosis (bar = 50 µm). Images represent no (i), weak (ii), moderate (iii), and strong (iv) staining intensity for ARG1. d Kaplan–Meier curve showing higher survival probability for n = 53 patients demonstrating low ARG1 transcript levels (lower quartile Q1) as compared to n = 53 patients with elevated (upper quartile Q3) expression levels of the gene. P = 0.0246 has been computed with the Cox proportional hazards model with age, clinical stage, and tumor grade included in the analysis. e Arginase activity in plasma of n = 81 OvCa (staging I–III) patients at the time of diagnosis and of 10 healthy controls (NC) determined in a colorimetric assay. Data show means ± standard deviation (SD), *P = 0.0024; **P = 0.0005; ***P < 0.0001, Kruskal–Wallis test with Dunn’s multiple comparison test. For every patient the mean activity of three independent measurements is shown. f Percent survival of n = 81 OvCa patients with high plasma arginase activity (two upper quartiles, pink) and low plasma arginase activity (two lower quartiles, blue). P = 0.0172 high (≥7.5 U ml⁻¹) vs. low (<7.5 U ml⁻¹) ARG activity, log-rank test, blue/pink shading −95% confidence interval. Source data for panels a and e are provided as a Source Data file