The main findings of this study are that treatment of C26 colon carcinoma cells-bearing mice with desipramine or fluoxetine: 1) increases the metastatic potential of C26 cc cells to the liver; 2) inhibits the proliferative activity of splenocytes; and 3) decreases the production of pro-inflammatory cytokines (IFN-γ, IL-1β) whilst increasing the production of the anti-inflammatory cytokine IL-10. The gene discussed is IFNG; the disease is colon carcinoma.