LEP and neoplasm: Taken together, our results reveal that leptin decreases the expression of critical pro-inflammatory cytokines, chemokines and RNI in macrophages [IL-12, TNFα, MIP-2 (CXCL2) and NO] yet significantly upregulates the pro-inflammatory and tumor-promoting IL-6, although it does not seem to modulate main anti-inflammatory molecules in macrophages (as IL-10).