Due to the multifaceted roles of STAT3 and opposing roles between this protein and STAT1 [13, 28] along with previous reports that C12-HSL can downmodulate STAT3 in breast carcinoma cells [15], we investigated the effect of C12-HSL on changes in both gene and protein expression of these molecules in PCa cells. The gene discussed is STAT3; the disease is breast carcinoma.