TNF and major depressive disorder: The Dwivedi group focused on epigenetic mechanisms of depression and suicide and recently reported that proinflammatory cytokines (e.g., TNF-α) and miR-19a-3b were up-regulated in the dorsolateral prefrontal cortex (DLPFC) in suicide victims, and both molecules were increased in the peripheral blood mononuclear cells of depressed patients with severe suicidal ideation (69).