NOS2 and adenocarcinoma: Interestingly, Kudo et al. [96] reported that PEG-b-P(l-Arg) nanoparticle engulfed by the activated macrophages suppressed the growth of C26 adenocarcinoma cells in Balb/c mice at a high concentration of NO, while it promoted angiogenesis at a low concentration, since M1 macrophages are known to overexpress inducible nitric oxide synthase (iNOS) to produce the cytotoxic nitric oxide (NO) from l-arginine as a substrate [97].