IL1B and neoplasm: Our data show that a single injection of anti‐miR223 PCs effectively reprograms leukocytes at the injected tumor site, leading to a transient high pro‐inflammatory phenotype, as revealed by anti‐IL1β immunostaining, extending for up to 6 days post treatment (dpt), but this diminished to control levels at later timepoints (10 dpt) (Figure 7J–V).