PTGS2 and neoplasm: Very recently, Zhang C. et al. [113] found that the tumoricidal action of n-3 PUFAs on LoVo and RKO colorectal cancer cells in vitro was associated not only with the decreased production of pro-inflammatory PGE2 and LTB4, COX-2, arachidonate 5-LOX and microsomal PGE synthase expression, but also with the increased formation of anti-inflammtory LXA4, supporting the hypothesis that LXs, resolvins and protectins have a direct growth inhibitory action on tumor cells; in contrast, 5-FU produced opposite effects on these indices.