INCREASED PLASMA-LEVEL OF CHOLESTEROL-5-BETA,6-BETA-EPOXIDE IN ENDOMETRIAL CANCER-PATIENTS

Plasma levels of alpha- and beta-isomers of cholesterol-5, 6-epoxides were quantitated in a pilot study of 9 women with endometrial cancer a nd 9 race- and age-matched control women by isotope dilution gas chrom atography/mass spectrometry. Endometrial cancer cases had significantl y higher cholesterol-5 beta,6 beta-epoxide levels than the controls (P = 0.01). The mean plasma beta-epoxide level was 0.71 +/- 0.46 ng/ml f or the cases and 0.35 +/- 0.25 ng/ml for the controls. No significant differences were found between the plasma alpha-epoxide levels of the cases and the controls. Plasma levels of various carotenoids, tocopher ols, and ascorbic acid were also quantitated by high performance liqui d chromatography. An inverse correlation was present between the plasm a levels of cholesterol-5 beta,6 beta-epoxide and cis-lutein/zeaxanthi n (P = 0.01). These data suggest a possible role for cholesterol-5 bet a,6 beta-epoxide as a biomarker of endometrial cancer risk. Further st udies are warranted to investigate the possible association between th e oxidation products of cholesterol and endometrial cancer and to dete rmine the interactive role of antioxidants.