In patients with malignant diseases, characteristic alterations in the
expression of CD44 protein and their variants were found. For the pre
sent study, the serum concentrations of the standard isoform CD44 std
and the two variant isoforms CD44 v5 amd CD44 v6 were measured by ELIS
A in patients with prostate cancer (n = 49), benign prostatic hyperpla
sia (n = 30), renal cell carcinoma (n = 31) and bladder cancer (n = 29
). The data were compared with the results of 30 healthy men and 30 he
althy women. The sCD44 v5 concentrations in patients with prostate can
cer (p < 0.01), benign prostatic hyperplasia (p < 0.01) and men with r
enal cell cancer (p < 0.01) were significantly lower than those measur
ed in the male control group. The sCD44 v5 concentrations observed in
male patients with bladder cancer were lower than in the male control
group (p < 0.05). Only in one group the concentration of sCD44 std dif
fered significantly from the others. The sCD44 std concentration in ma
le patients with renal cell cancer was significantly lower than in the
male control group (p < 0.01). Other significant differences were not
found. In contrast to results observed in other carcinomas, the deter
mination of soluble CD44 proteins in serum cannot be recommended as a
marker for urological malignancies.