S100A10 and depressive symptom measurement: The levels of mRNA and protein of p11 are downregulated in the hippocampus of rodents with depression-like phenotype and the peripheral blood mononuclear cells of depressed patients.23, 24 Furthermore, decreased p11 mRNA levels are also observed in the hippocampus of suicide victims.25 Interestingly, the overexpression of p11 can rescue the depression-like phenotype in p11 knockout mice, and selective serotonin reuptake inhibitors or tricyclic antidepressants promote the expression of p11 in the frontal cortex and hippocampus of rodents.23, 26