CCL2 and neoplasm: Furthermore, studies have not only verified the direct contact effect of GAMs with blood vessels around and inside the tumor using allografted mice but have also detected elevated levels of various angiogenesis-inducing factors, such as VEGF, VEGFR1, CCR2, CXCR4, CCL2/5, and CXCL2/10/14 (14, 90–93).