ARG1 and urinary bladder carcinoma: Moreover, the tumor-related macrophages could secrete the type I collagen via activating the PI3K/AKT signaling pathway to stimulate the development of bladder cancer; meanwhile, the number of macrophages and the expression of M2 macrophage-associated genes (ARG-1, IL-10, and TGF-β) were remarkably elevated in malignant bladder tumor tissue samples (46).