CD274 and cancer: In a randomized controlled trial (RCT) of patients with various advanced cancers (n=296), low arginine levels at baseline (<42 uM) were significantly associated with worse OS [median OS = 38.8 months vs. 24.6 months; HR = 1.57; 95% CI: 1.10 – 2.24; P = 0.012] and associated with high PD-L1 expression in cells, indicating that a combinatory therapeutic approach may yield favorable outcomes (26).