CTSB and neoplasm: On the other hand, TAMs establish a pro-tumor microenvironment that influences the origin, progression, dissemination, and drug resistance of tumor cells in several ways, such as:(i) TAMs promote tumor cell growth and metastasis by secreting EGF (40), matrix metallopeptidase (MMP)s (41, 42), Wnt family member (WNT) 5A, cathepsin B, semaphorin 4D and IL1β (43).