As the role of CCR2 in regulation of autoimmunity remains contradictory, overwhelming evidence supports that the CCL2/CCR2 axis activity largely favors progression and metastasis of tumor by attracting suppressive monocytes and Tregs (12, 13), though any chemokine/chemokine receptor can have both pro-tumor and anti-tumor action (1). The gene discussed is CCL2; the disease is neoplasm.