Role of serum polyunsaturated fatty acids in the development of colorectal cancer

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.