Whereas fatty acid desaturase 1 encoded by FADS1 is a key rate-limiting enzyme for the synthesis of polyunsaturated fatty acids (e.g., arachidonic acid), its catalytically generated metabolites (arachidonic acid, leukotrienes, etc.)are known to be potent pro-inflammatory mediators, which have been closely associated with chronic inflammation and the tumor microenvironment [50]. This evidence concerns the gene FADS1 and neoplasm.