CELLULAR FIBRONECTIN IN SERUM AND PLASMA - A POTENTIAL NEW TUMOR-MARKER

The concentration of cellular fibronectin (cFN) containing the extra d omain A (EDA) was measured in 479 plasma and 300 serum samples from he althy blood donors by a competitive enzyme immunoassay (EIA). Serum an d plasma samples contained low concentrations of EDAcFN. The mean conc entration of EDAcFN was higher in plasma (2.46 mg l(-1)) than in serum (0.30 mg l(-1)). No significant differences between sexes or age grou ps were found. The EDAcFN concentrations were also measured in 120 pat ients with various malignancies. The mean values in serum were 4.28 mg l(-1), 2.01 mg l(-1) and 5.18 mg l(-1) in patients with digestive tra ct malignancies, breast cancer and a group of miscellaneous cancers re spectively. In plasma, the corresponding values were 12.26 mg l(-1), 4 .38 mg l(-1) and 11.12 mg l(-1) respectively. The serum EDAcFN concent ration was higher than the 97.5th percentile level of healthy blood do nors in 86% of patients with digestive tract and in 76% with miscellan eous malignancies. In patients with breast cancer 60% had elevated lev els of EDAcFN. The corresponding figures for plasma samples in patient s with digestive tract and miscellaneous malignancies were 79% and 71% respectively. In patients with breast cancer only 30% had elevated pl asma levels of EDAcFN. The mean values in serum and plasma of 20 patie nts with benign diseases were below the cut-off levels. Consistent wit h the EIA results, Western blotting revealed increased amounts of EDAc FN in blood samples from cancer patients. Pregnancy did not affect the EDAcFN concentration. The mean values in 20 pregnant women were below the cut-off levels.