OBJECTIVES: We aimed on effect of supernatant derived from prostate cancer cell line PC-3 on M1/M2 functional polarization in macrophages. BACKGROUND: Cytokines play an important role in carcinogenesis. Most of them are produced by macrophages. Macrophages are divided into groups M1 or M2. Classical phenotype macrophages M1 support pro-inflammatory effects and produce pro-inflammatory cytokines, such as interleukin 6 (IL-6), interleukin 12 (IL-12), tumor necrosis factor alpha (TNF-alpha). Macrophages exhibiting a phenotype M2 secrete anti-inflammatory cytokines, e.g. interleukin 10 (IL-10), transforming growth factor beta (TGF-beta). METHODS: Peripheral blood monocytes were cultivated for 7 days and during this time went through a differentiation into macrophages. Macrophages were stimulated for 24 hours by lipopolysaccharide (LPS) as a positive control and cultivated with supernatant for another 24 hours. RESULTS: Macrophages cultivated without LPS and without supernatant were used as negative control. Relative expression of IL-6, IL-10, IL-12 and TNF-alpha was measured by Quantitative real-time PCR. Expression of pro-inflammatory cytokines was lower in macrophages with supernatant compared to positive control. CONCLUSION: Expression of pro-inflammatory cytokines was lower in macrophages with supernatant (M phi+sup) compared to positive control (M phi+LPS). Effect of the supernatant on expression of IL-6, IL-10, IL-12 and TNF-alpha was not confirmed (Tab. 1, Fig. 5, Ref. 15). Text in PDF www.elis.sk.