Profiling lipoxygenase metabolism in specific steps of colorectal tumorigenesis.

Lipoxygenases (LOX) are key enzymes for the oxidative metabolism of polyunsaturated fatty acids into biologically active products. Clinical data on comparative levels of various LOX products in tumorigenesis are lacking. Therefore, we examined the profiles of several LOX products (5-LOX, 12-LOX, 15-LOX-1, and 15-LOX-2) by liquid chromatography/tandem mass spectrometry in the major steps of colorectal tumorigenesis (normal, polyp, and cancer) in a clinical study of 125 subjects (49 with normal colon, 36 with colorectal polyps, and 40 with colorectal cancer) who underwent prospective colorectal biopsies to control for various potential confounding factors (e.