Two-site ELISA for the quantitative determination of fatty acid synthase

Fatty acid synthase (FAS) is an enzyme which plays a central role in the de novo biosynthesis of fatty acids, FAS is selectively expressed in certain human cancers and therefore is a putative tumor marker. We developed an enz yme-linked immunosorbent assay (ELISA) for measuring FAS, and investigated its expression and clinical features. In this two-site sandwich ELISA, a po lyclonal antibody was used as a capture on Nunc MaxiSorp ELISA/EIA modules and a monoclonal antibody labeled with biotin was used as a signal antibody . The assay was linear with no cross-reactivity with other tumor markers. T he within- and between-run CVs were <10% and the detection limit was 0.15 a rbitrary Units/l. Recoveries were 91.4-105.1%. FAS was stable in buffer at 4<degrees>C for more than 10 days and stable at 37 degreesC for 2 days. In human serum. FAS levels were significantly higher in patients with boast (1 .01 +/- 0.71 Units/l mean +/- S.D.). prostate (0.79 +/- 0.76 Units/l). colo n (0.89+/-0.49 Units/l). and ovarian (0.84 +/- 0.9 Units/l) cancers compare d to normal subjects (0.27+/-0.09 Units/l. P<0.01). This assay is sensitive , accurate, and precise and can distinguish between patients with various t ypes of cancer and normal subjects. (C) 2001 Elsevier Science B.V. All righ ts, reserved.