SOLUBLE RECEPTOR FOR UROKINASE PLASMINOGEN-ACTIVATOR IN BOTH FULL-LENGTH AND A CLEAVED FORM IS PRESENT IN HIGH-CONCENTRATION IN CYSTIC FLUID FROM OVARIAN-CANCER
K. Wahlberg et al., SOLUBLE RECEPTOR FOR UROKINASE PLASMINOGEN-ACTIVATOR IN BOTH FULL-LENGTH AND A CLEAVED FORM IS PRESENT IN HIGH-CONCENTRATION IN CYSTIC FLUID FROM OVARIAN-CANCER, Cancer research, 58(15), 1998, pp. 3294-3298
We assayed the levels of soluble urokinase plasminogen activator recep
tor (su-PAR) with an ELISA in various body fluids from 77 patients wit
h benign or malignant ovarian tumors, histologically classified as fol
lows: benign; possibly malignant (borderline); and well, intermediatel
y, and poorly differentiated malignant. The concentration of su-PAR in
fluid from malignant cysts was extremely high, similar to 10-fold hig
her than the concentration in ascitic fluid and similar to 100-fold hi
gher than that in blood. Also, the concentration in malignant cysts wa
s similar to 10-fold higher than the concentration in benign cysts. Su
ch high concentrations of su-PAR were found not only in truly malignan
t but also in possibly malignant cysts. Thus, we suggest that the conc
entration of su-PAR in cystic fluid can serve as a marker, allowing ea
rly diagnosis of malignant ovarian cysts. The concentration of su-PAR
in fluid aspirated transvaginally with ultrasonographic guidance can b
e used to discriminate possibly and truly malignant cysts from benign
cysts without surgery. The high concentrations of su-PAR in ovarian cy
stic fluids allowed us to characterize the molecular forms. Cross-link
ing of a radiolabeled ligand to the receptor demonstrated that at leas
t a fraction of su-PAR was able to bind the ligand. A cleaved form of
the receptor constituting domains 2 and 3 was detected with Western bl
otting. The cleaved receptor, which is devoid of the ligand-binding do
main 1, has not previously been demonstrated in body fluids; it has on
ly been demonstrated on cell surfaces, su-PAR domains 2 and 3 were fou
nd in cystic fluids from both malignant and benign ovarian tumors.