CCL2 and depressive symptom measurement: Other genes commonly investigated are those related to glia or astrocyte cell functioning or proliferation; for instance, we found that the mRNA expression of the chemokines CXCL1, CXCL2, CXCL3 and CCL2 was significantly decreased in the prefrontal cortex (PFC) of suicide completers who had depression when compared with non-suicide individuals [7].