IL6 and neoplasm: To overcome the high toxicity and better STAT3 silencing effect, PEI was modified with stearic acid (StA) to deliver STAT3 siRNA to induce tumor apoptosis in B16 melanoma cells, it showed higher potency in STAT3 silencing with a significant induction of IL-6 secretion, 2.5 times higher expression of cellular Caspase3 and reduction of VEGF production, in comparison to PEI complexes alone (129).