Pr. Huber et al., SERUM-FREE PROSTATE-SPECIFIC ANTIGEN - ISOENZYMES IN BENIGN HYPERPLASIA AND CANCER OF THE PROSTATE, The Prostate, 27(4), 1995, pp. 212-219
Prostate specific antigen (PSA) in serum of patients with benign prost
atic hyperplasia (BPH) or prostate cancer (P-CA) not bound to alpha-1-
antichymotrypsin (ACT) was analyzed by chromatofocusing. The procedure
allowed the simultaneous separation of complexed and free PSA and the
fractionation of the free PSA fraction into several isoenzymes. The d
etection of the isoenzymes was strongly dependent on the combination o
f: antibodies introduced in the applied commercially available immunoa
ssays (Cobas(R) Core, Delfia(R)). Isoenzymes in sera of patients with
benign prostatic hyperplasia were mainly situated in the pi range of 6
.6 to 7.3. Isoenzymes in sera of prostate cancer patients or in PSA fr
om LNCAP cells were mainly situated in the pi range 7.0 to 8.3. Neuram
inidase treatment of the sera shifted the isoelectric points of all th
ree sources towards more basic pHs. An irregular glycosylation process
in the dysplastic cells of the prostate is suggested to be the cause
for the shift of the isoelectric points. The difference of isoenzyme d
istribution along the pH axis is discussed as a diagnostic tool to dif
ferentiate between BPH and P-CA. (C) 1995 Wiley-Liss, Inc.