IL10 and neoplasm: For example, LPS-activated macrophages become unable to reactivate a large fraction of their pro-inflammatory genes a few hours following re-stimulation, and yet they retain the ability to induce the expression of anti-inflammatory cytokines (e.g., IL-10) in vitro[37]; in early tumor development, local macrophages are the M1 phenotype, while after tumor formation, local macrophages differentiate to the M2 phenotype [38].