We aimed to investigate the role of serum levels of polyunsaturated fatty acid (PUFA) in the development of colorectal cancer (CRC). Serum levels of n-3 and n-6 PUFA in 69 healthy control (Ctrl), 62 benign colorectal polys (CRP) and 100 CRC patients were detected by gas chromatograph. The adjusted odds ratio (OR) by quartiles of n-3 and n-6 PUFA were analyzed. During the process of Ctrl to CRP, total n-3 PUFA (OR=0.159, P<0.001), total n-6 PUFA (OR=0.190, P<0.001), C20:5 n-3 (OR=0.263, P=0.030), C22:6 n-3 (OR=0.125, P<0.001), and C18:2 n-6 (OR=0.299, P=0.025) were inversely associated with CRP risk. The ratio of total n-6 PUFA and total n-3 PUFA (OR=4.667, P=0.002), and the ratio of C20:4 n-6 and (C20:5 n-3+C22:6 n-3) (OR=6.000, P<0.001) were positively associated with CRP risk. During the process of CRP to CRC, total n-3 PUFA (OR=4.059, P=0.007), total n-6 PUFA (OR=8.146, P<0.001), C22:6 n-3 (OR=3.789, P=0.048), and C18:2 n-6 (OR=3.667, P=0.045) were positively associated with CRC risk. The ratio of C20:4 n-6 and (C20:5 n-3+C22:6 n-3) (OR=0.588, P=0.001) was inversely associated with CRC. In conclusion, our results found that the total n-3 PUFA, C22:6 n-3, the total n-6 PUFA, C18:2 n-6, and the ratio of C20:4 n-6 and (C20:5 n-3 +C22:6 n-3) played controversy role in the process of CRP and the process of CRC, and may provide nutritional intervention suggestions for the clinical practice.
Keywords: Polyunsaturated fatty acids; colorectal cancer; colorectal polys; odds ratio.