However, the biological effect of CCL2 may be biphasic and more related to recruitment than polarization as suggested by a study where low-level CCL2 secretion by non-tumorigenic melanoma cells led to modest monocyte infiltration and stimulation of tumor formation due to increased angiogenesis, while high CCL2 levels were associated with massive monocyte infiltration into the tumor mass, leading to its destruction (142). The gene discussed is CCL2; the disease is melanoma.