AIM: To investigate the relationship of serum levels of polyunsaturated fatty acid(PUFA) with kinds of cytokines in colorectal cancer(CRC).METHODS: Serum samples of 100 CRC patients were collected. The concentration of total n-3 PUFA which included C18:3 n-3, C20:5 n-3, C22:5 n-3, C22:6 n-3 and the total n-6 PUFA included C18:2 n-6, C18:3 n-6, C20:3 n-6, C20:4 n-6, and C22:5 n-6 were detected onGC-2010 Plus Gas Chromatograph with a Omegawax TM 250 column. Cytokines were detected by Mag Plex TM-C microspheres. P values for the trend were estimated by creating a continuous variable using the median value within quartiles.RESULTS: Interleukin-6(IL-6) showed significantly positive association with the C20:4 n-6(P for trend = 0.004). Interferon gamma(IFN-γ) showed significant positive association with the C22:5 n-3(P for trend = 0.035). IL-8 and matrix metalloproteinase-9(MMP-9) showed significant inverse association with the C22:6 n-3(P for trend = 0.049, and 0.021). MMP-2 showed significant inverse association with the C20:5 n-3(P for trend = 0.008). MMP-7 showed significantly positive association with the ratio of n-6 PUFA and n-3 PUFA(P for trend = 0.008). MMP-7 also showed significantly inverse association with the ratio of C20:4 n-6 and(n-6 PUFA + n-3 PUFA)(P for trend = 0.024). IL-10(P for trend = 0.023) and IL-6(P for trend = 0.036) showed significantly positive association with the ratio of C20:4 n-6 and C20:5 n-3.CONCLUSION: Our data suggested that serum levels of PUFA is related to the inflammation of CRC, and also play different role in regulation of immune response. To investigate the relationship of serum levels of polyunsaturated fatty acid (PUFA) with kinds of cytokines in colorectal cancer (CRC). METHODS: Serum samples of 100 CRC patients were collected. The concentration of total n-3 PUFA which included C18: 3 n-3, C20: 5 n-3, C22: 5 n-3, C22: 6 n-3 and the total n-6 PUFA include C18: 2 n-6, C18: 3 n-6, C20: 3 Cytokines were detected by Mag Plex ™ -C microspheres. P values ​​for the trend were n-6, C20: 4 n-6, and C22: 5 n-6 were detected on GC-2010 Plus Gas Chromatograph with a Omegawax ™ 250 column. estimates by creating a continuous variable using the median value within quartiles.RESULTS: Interleukin-6 (IL-6) showed significant positive association with the C20: 4 n-6 (P for trend = 0.004) showed significant positive association with the C22: 5 n-3 (P for trend = 0.035). IL-8 and matrix metalloproteinase-9 (MMP-9) showed significant inverse association with the C22: 6 n-3 0.049, and 0.021). MMP-2 showed signific MMP-7 was significantly positive association with the ratio of n-6 PUFA and n-3 PUFA (P for trend = 0.008). MMP-7 also showed significant inverse association with the ratio of C20: 4 n-6 and (n-6 PUFA + n-3 PUFA) (P for trend = 0.024) P for trend = 0.036) showed significantly positive association with the ratio of C20: 4 n-6 and C20: 5 n-3.CONCLUSION: Our data suggested that serum levels of PUFA is related to the inflammation of CRC, and also different role in regulation of immune response.